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Used Power Catamarans For Sale

photo of 124' Dynamic Custom 38M 2025

124' Dynamic Custom 38M 2025

$ 28,000,000

Ft. Lauderdale, United States

photo of 115' New Zealand Yachts Wave Piercer 2005

115' New Zealand Yachts Wave Piercer 2005

$ 5,900,000

Dania Beach, United States

photo of 110' JFA 2012

110' JFA 2012

$ 19,116,750

Enroute to Newport, United States

photo of 107' Custom Cruiser Catamaran 2023

107' Custom Cruiser Catamaran 2023

$ 2,023,500

Mannheim, Germany

photo of 103' Custom Fjellstrand 1983

103' Custom Fjellstrand 1983

$ 1,999,000

Virgin Islands (British)

photo of 100' Extra Yachts X30 VILLA 2025

100' Extra Yachts X30 VILLA 2025

$ 17,998,500

Ancona, Italy

photo of 88' Sunreef Sunreef 88 DD 2017

88' Sunreef Sunreef 88 DD 2017

$ 6,675,000

Turks And Caicos Islands

photo of 85' Mares Power Cat 85 1997

85' Mares Power Cat 85 1997

$ 1,698,800

Seattle, United States

photo of 82' Sunreef Sunreef 82 DD 2012

82' Sunreef Sunreef 82 DD 2012

$ 3,305,760

Sardinia, Italy

photo of 80' Mystique Yachts Silhouette 800 2023

80' Mystique Yachts Silhouette 800 2023

$ 4,740,000

Fort Lauderdale, United States

photo of 80' CUSTOM US BUILT Morelli/Miller 1991

80' CUSTOM US BUILT Morelli/Miller 1991

Phillipsburg, Saint Martin

photo of 78' Naval Yachts 2024

78' Naval Yachts 2024

$ 4,792,500


Power Catamarans, or "Power Cats" as they are often referred to, are one of the fastest growing segments in the marine industry. Sailing Catamarans have long been the preferred choice of sailors in the Caribbean because of the advantages of having two hulls and a wide beam. For a family enjoying a catamaran experience though, sailing becomes more of a hassle for some. For this reason, many of the yacht charter destinations now offer just as many power cats as sailing cats in their selection. This progression of how the catamarans are used spurred many of the catamaran manufacturers to start producing more power cats.

Yacht Image


When we hear someone has the bug for a power catamaran, it’s a gleaming opportunity for us to elaborate on their wonderful advantages. Different from the benefits of sailing, of course, there’s lots to entice a buyer with from expanded living areas, stability, storage capabilities, and fuel efficiency.

Far from being known as a new trend, the catamaran design has been around since 5th Century India. Sailing catamarans have been a popular choice for cruisers for years, but adding full power to it has really become popular in the last decade.

Below are some of the most well-known power catamaran brands on the market today:

  • Aquila Boats
  • Endeavour Catamarans
  • Fountaine Pajot
  • Horizon Power Catamarans
  • Leopard Power Catamarans

Here are some frequently asked questions regarding buying a power catamaran

What is a power catamaran?

Power catamarans are simply defined as a multi-hull power boats. Power Catamarans have become increasingly popular in recent decades among recreational boaters for their stability, maneuverability, and roomy, comfortable ride. Although sailing catamarans have been on the seas for centuries, perhaps millennia, recreational power catamarans got their start in the 1970s.

example of power catamaran

Who invented the catamaran boat?

Catamarans originated with Polynesian people who built catamarans and outrigger canoes to travel to distant islands of the Pacific and Indian Oceans and by fishermen in Tamil Nardu, India for their stability in various sea conditions. Western development of a catamaran vessel began in the mid 1600s, to allow faster sailing in shallower waters and lighter wind, but didn’t meet with commercial success, and it wasn’t until the 1800s that further development led to the filing of a US Patent. Power catamarans were developed in the early 20th century as submarine salvage vessels and high-speed military transport vessels. The more recent development of the recreational power catamaran combined the best features of a motor yacht - luxurious living and deck area with the stability, speed, and efficiencies of a catamaran. One of the most popular examples is the 43ft Lagoon.

example of lagoon 43 power cat

What are some types of catamarans?

Power or Sailing, Trimaran, Fishing (World Cat, Invincible, Barker, Calcutta, Insetta, and the custom Renaissance Prowler are among today’s best, offering stability, improved ride in rough seas, and an open deck layout), Cruising, Passenger (Ferries), Commercial/Industrial, Military, Security & Tactical Support, TrawlerCats, and Long-Range Luxury Catamaran Yachts are some of the catamarans on the water today.

What is the difference between conventional, wave-piercing, and SWATH catamaran hulls?

Traditional catamaran hulls are more banana-shaped, designed to ride on top of waves, with the geometry of the vessel creating stability, whereas the wave-piercing hulls extend forward and are reversed—longer at bottom than top/bow and sharper, allowing them to slice through waves for greater speed and less pitching, due to their lower buoyancy. More racing catamarans are built with wave-piercing hull technologies for speed advantages. Cruising catamarans in the superyacht category are utilizing wave-piercing hulls for the smoothness and performance advantages. Large passenger ferries and military catamaran ships utilize this type of hull for its speed and smooth ride through waves; the bridge deck may be configured like a regular v-hull, allowing it to penetrate wave crests. The SWATH (small water-plane area twin hull) catamarans employ tubular, submarine-like hulls that are completely submerged and connected by pylons to the bridge deck using a small cross section at the waterline. This type of hull was invented in the mid-1930s and is used for large research vessels and military craft for running in heavy seas as displacement volume is completely below waterline. This enables the ship to resist pitch and heaving, as there is no possibility of hull planing. Today’s builders of cruising power catamarans utilize the best hull technologies for increased efficiencies and safety.

Is a pontoon boat a type of catamaran?

Depending on boat size, pontoon boats ride on 2 or 3 aluminum flotation tubes called pontoons, that support and are covered by the open deck, and are not accessible from the deck; they serve to float the boat. A railing with fence paneling or seating upholstery runs along the deck perimeter, and they are typically outfitted for lounging and entertaining (nicknamed “party barges”), though many today are luxurious, and as speedy as runabouts and used for watersports. There are two types of pontoons: recreational and houseboats. Catamarans differ greatly in that the main deck rests on 2 or 3 (trimaran) hulls that are accessible living and/or storage space, and catamarans can be built with a flybridge deck. The catamaran hull is built for cruising/running offshore and inshore waterways, whereas the pontoon boats are open deck boats primarily designed for lakes, bays, rivers that are quieter waters. Catamarans tend to be wider and larger than pontoon boats, but each is a distinct category with its own purpose and market. Pontoons tend to serve the entry-level family recreational market. Both have seen an increase in popularity in the recreational boating industry.

Are power catamarans better than monohull powerboats?

Catamarans offer more deck and interior space per foot than monohulls, meaning a 40ft powercat can have as much space (in and out) as a 50ft monohull powerboat. Even a smaller powercat can have easily accessed 3-4 cabins with opening ports in hull windows for ventilation and light, plus the greater privacy of separate hull space, an ideal feature for charters. Inherently, the wide-apart hull configuration provides a more stable platform while underway or to stay level at anchor, unlike a monohull that can roll. Having twin engines and propellers set wide apart allows catamarans greater maneuverability and a shallower draft for island cruising—some catamarans can be beached! Having two hulls creates inherent redundancy with engines, props, water pumps, and extra space for additional equipment like generators, watermakers, and more. Catamarans with wave-piercing hulls have even greater efficiencies.

( Seen below: The living areas on a catamaran offer great space inside and out. )

interior living area on a catamaran

Of course, there are some disadvantages, as with any category of vessel. One drawback is the cost to store and maintain a catamaran is higher, as marina dockage isn’t always accommodating of the catamaran’s greater beam and with two hulls/engines, maintenance and detailing costs may double. Haul-out costs are higher as well. The preference of one type of boat over another is completely personal; which best meets your priorities and usage plans? Do a cost benefit analysis—does the boat’s features and benefits outweigh any drawbacks?

What are the most popular current brands of cruising power catamarans?

Current brands to consider are Lagoon, Leopard (Robertson & Caine), Fountaine-Pajot, Sunreef, Nautitech, Horizon, Aquila, Makai, Bali Catspace MY, Hudson Powercat, Aspen Power Catamarans, Horizon, Endeavour TrawlerCat, Heliotrope 48, and the Leen 56 (a new trimaran long range cruiser and liveaboard). PDQ is no longer in production, but still popular, especially for cruising the eastern Great Loop. Common to all are the alfresco relaxation deck areas that seamlessly blend with interior deck area. There are also many one-of-a-kind custom power catamarans.

What does a 43-45 ft power catamaran cost?

Pre-owned 43-45ft power catamarans from 2010 to 2019 ranged in price from $398,000 to $1,075,000 for a median of $736,500. The main brands were Leopard, Fountaine Pajot, Aquila, and Lagoon. From 2000 to 2009, the price ranged from $202,000 to $528,000 for a median of $365,000. Main brands were Leopard, Fountaine Pajot, and Lagoon. Of course, there are other costs to consider, such as marina dockage, service and maintenance including haul-outs, and insurance, to mention a few.

What are the best power catamarans for offshore cruising?

According to the Oct 2020 issue of Passagemaker magazine, the Nautitech 47 power catamaran features load-carrying semi-displacement hulls give the Nautitech 47 a distinct performance advantage for bluewater (ocean) cruising. Other recommended models are the new Leen 56 trimaran long range cruiser designed for Transatlantic voyages. The main diesel engine is in the center hull and electric drives are in the two outer hulls (called amas). The Leopard 53 Powercat can be run from the lower helm with excellent visibility in air-conditioned comfort and features 6’8” and 6’10” headroom! Bali Catspace Motor Yacht (Catana Group) is nearly 39ft of luxurious outside/inside living space. Utilizing the latest innovations, the shape of her hulls and integral deck gives this power catamaran excellent seakeeping qualities. The 60 Sunreef Power is a versatile, modern motoryacht in Sunreef Yachts’ sporty Power line-up of catamarans in 60, 70, 80, and 100ft lengths. These are just a few examples. Fountaine-Pajot has been building catamarans since 1976; latest models are as luxurious and seaworthy as any world-class power motoryacht, with catamaran advantages.

Lagoon, Fountaine-Pajot, Sunreef, Leopard, Horizon, and other power catamarans are extremely popular for island charter cruises as they offer the power catamaran advantages of stability, speed, efficiency, spaciousness (wide beam interiors, private staterooms below deck), and relaxation with lots of deck space and 360-degree panoramic views! With their shallower draft, the swift powercats are great for island hopping in the Bahamas or BVI, and elsewhere in the world with beautiful archipelagos, reefs, and pretty islands to explore!

Read These Other Articles Related To Power Catamarans:

  • Who Makes The Best Power Catamarans
  • Are Power Catamarans Good In Rough Water?

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power boat catamaran for sale

1 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Starboard side view of catamaran in water. 3960 [empty string] [empty string] [empty string] 1 [empty string] [empty string] [empty string] 18
2 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Gray bedding in stateroom with light wood accents. 3849 [empty string] [empty string] [empty string] 2 [empty string] [empty string] [empty string] 18
3 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Light gray couch with patterned pillows in front of galley. 3848 [empty string] [empty string] [empty string] 3 [empty string] [empty string] [empty string] 18
4 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] White helm chair in front of wood table and gray bench seat. 3844 [empty string] [empty string] [empty string] 4 [empty string] [empty string] [empty string] 18
5 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] yes [empty string] Front view of catamaran cruising with two people on bow. 3056 [empty string] [empty string] [empty string] 5 [empty string] [empty string] [empty string] 18
6 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] View from outside galley at night. 3852 [empty string] [empty string] [empty string] 6 [empty string] [empty string] [empty string] 18
7 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Wood table with corner booth seat. 3847 [empty string] [empty string] [empty string] 7 [empty string] [empty string] [empty string] 18
8 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Galley with gray countertops and wood cabinets. 3846 [empty string] [empty string] [empty string] 8 [empty string] [empty string] [empty string] 18
9 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] White sink with silver hardware and glass door to shower. 3850 [empty string] [empty string] [empty string] 9 [empty string] [empty string] [empty string] 18
10 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Gray bedspread with white blanket draped across. 3851 [empty string] [empty string] [empty string] 10 [empty string] [empty string] [empty string] 18
11 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Twin beds with gray and white comforters. 3845 [empty string] [empty string] [empty string] 11 [empty string] [empty string] [empty string] 18
12 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Teak wood and gray couch on aft deck. 3854 [empty string] [empty string] [empty string] 12 [empty string] [empty string] [empty string] 18
13 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Power catamaran cruising past lighthouse. 449 [empty string] [empty string] [empty string] 13 [empty string] [empty string] [empty string] 18
14 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Wood table and bench seat leading to galley with bar area. 3857 [empty string] [empty string] [empty string] 14 [empty string] [empty string] [empty string] 18
15 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Brown countertop with built in sink in galley. 3856 [empty string] [empty string] [empty string] 15 [empty string] [empty string] [empty string] 18
16 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Black barstools next to countertop in galley. 3855 [empty string] [empty string] [empty string] 16 [empty string] [empty string] [empty string] 18
17 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Bed with black bottom and cream colored comforter. 3858 [empty string] [empty string] [empty string] 17 [empty string] [empty string] [empty string] 18
18 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Front view of catamaran cruising in water. 3058 [empty string] [empty string] [empty string] 18 [empty string] [empty string] [empty string] 18
19 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Dark gray couch leading into galley with bar stools. 1770 [empty string] [empty string] [empty string] 19 [empty string] [empty string] [empty string] 18
20 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] yes [empty string] White sink above countertops next to hanging towel with Horizon logo. 453 [empty string] [empty string] [empty string] 20 [empty string] [empty string] [empty string] 18
21 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Yellow walled cabin with brown bed. 457 [empty string] [empty string] [empty string] 21 [empty string] [empty string] [empty string] 18
22 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] yes [empty string] Brown and gray tiled backsplash with white sink and vase. 455 [empty string] [empty string] [empty string] 22 [empty string] [empty string] [empty string] 18
23 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Coral patterned pillows on twin beds in cabin. 459 [empty string] [empty string] [empty string] 23 [empty string] [empty string] [empty string] 18
24 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Blue accented cabin with white comforter. 1771 [empty string] [empty string] [empty string] 24 [empty string] [empty string] [empty string] 18
25 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Gold textured comforter on bed in cabin with matching pillows. 1769 [empty string] [empty string] [empty string] 25 [empty string] [empty string] [empty string] 18
26 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Blue and gray tiled backsplash with sink and silver hardware. 1772 [empty string] [empty string] [empty string] 26 [empty string] [empty string] [empty string] 18
27 PC52 51' 6 [empty string] 22' 4' 3 jpg [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] [empty string] no [empty string] Aft deck dining set up with sunset in background. 490 [empty string] [empty string] [empty string] 27 [empty string] [empty string] [empty string] 18


The Horizon PC52 model answers the demand for a high-end power catamaran in the 50-foot range that is capable of true blue-water cruising. The PC52 offers extremely comfortable living spaces, with a functional three-stateroom layout, large galley and spacious salon, as well as all of the necessary amenities for extended cruising. She has been professionally designed and engineered to meet Horizon’s high standards for quality, and the PC52’s generous bridge deck clearance ensures the ride is efficient, smooth and stable, providing you the peace of mind you need when out on the open sea. The PC52 is available in both Open and Enclosed Flybridge versions.

PC52 Yacht


L.O.A 51' 6 15.70 meters
Beam 22' 6.71 meters
Draft 4' 3 1.30 meters
Displacement * 27.4 tons 60,451 lbs
Fuel Tank 800 gallons 3,028 liters
Water Tank 270 gallons 1,022 liters
Engines Twin Cummins QSB 6.7 550HP
Generators 13.5 kW (50Hz) or 17 kW (60Hz)

PC52 Yacht

LAYOUTS click to enlarge

PC52 Yacht

**Optional items may be shown in the layout that are not included in the base price**

PC52 Yacht


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power boat catamaran for sale

Power Catamaran Boats for sale

1-15 of 444

2001 Glacier Bay 2640 Renegade

2001 Glacier Bay 2640 Renegade

Melbourne Beach, Florida

Make Glacier Bay

Model 2640 Renegade

Category Power Catamaran Boats

Posted Over 1 Month

The Glacier Bay 2640 Renegade has been repowered with twin Mercury 150hp motors that have only approximately 15 hours. The motors are under warranty until Oct 27th, 2027, the warranty is transferable, and they are eligible for an extended warranty as well. The Bimini top looks to be in good shape. Much of the upholstery has been updated; the chrome hardware looks in good shape. The toilet pump needs to be replaced. The bottom paint is ready to update if it is going to be stored in the water. She has been stored covered on a lift but could use a nice cleaning and detailing. Stock #399782 ***SALE PENDING*** Wow! Take A Look At This Glacier Bay 2640 Renegade with Twin 2023 Mercury 150 HP motors with appx 15 Hours, Head, Stored Covered and Ready to Go! Looking for that smooth ride? Take a look at this Glacier Bay 2640 Renegade, which is now equipped with twin 2023 Mercury 150hp motors with approximately 15 hours and under factory warranty until October 2027! Knowledgeable boaters know a catamaran hull offers an exceptional level of comfort compared to traditional monohull vessels. The design of catamaran hulls allows the boat to glide more smoothly over the water, providing a stable and gentle ride that minimizes rocking and rolling. A catamaran hull offers greater stability, a smooth ride, reduced drag, enhanced handling, greater fuel economy, a shallow draft, and a large open deck space. This Glacier Bay has a draft of only 1' 8". This 2640 Renegade is a versatile vessel for anglers and pleasure seekers alike. Experience great performance with the upgraded twin 2023 Mercury 150 HP motors, ensuring a thrilling ride every time you hit the water. The Glacier Bay 2640 Renegade offers ample space for you and your entire crew with a large L-shaped bench seat, bow seating, and removable rear deck captain chairs. This Glacier Bay also has the convenience of an onboard head, which ensures your comfort on extended trips. Whether you're fishing, cruising, or simply enjoying a day on the water with family and friends, you will have accommodations for everyone. Your family will also appreciate the recessed telescopic stainless steel swim ladder and a swim platform, which allow for an easy entry and exit from the water; the large bimini top, which will provide the shade needed on those bright summer days; and the upgraded stereo. Some of her other features include ample compartment storage, a large bow casting platform with below-deck storage compartments, a full boat cover, and much more. Call today to make an appointment to see this Glacier Bay 2640 Renegade in beautiful Melbourne Beach, FL. Buyers should verify all features, specs, and conditions during the Buyer's due diligence process. Reason for selling is moving our of state..

2005 Glacier Bay 2680 Coastal Runner

2005 Glacier Bay 2680 Coastal Runner

Palmetto, Florida

Model 2680 Coastal Runner

This Glacier Bay is in good condition for her age. The seller just had the boat detailed and has a nice hull shine. The hull sides have a nice shine and are free from any major defects. The interior is clean and the electronics have been updated. The cabin is clean and ready for a new owner! Stock #388699 Power Catamaran! Offshore Ready! Just Detailed! Engines Run Great!! 2005 Glacier Bay 2680 Coastal Runner This is a nice power catamaran design with quality construction by Glacier Bay. This Coastal Runner features an interior cabin with room for two to sleep very comfortably and a plumbed head. The dual hull design with its wide beam, and high gunwales creates the perfect combination for a dry, stable ride, even in rough sea days. The cockpit features a wrap-around windshield and side windows with a hardtop overhead with two opening ports. The rear deck area has coaming pads for comfort, a huge live well and access to the integrated swim platform. There are plenty of rod holders and two fish boxes are in the floor. This design allows you to walk around the sides to the bow with handrails. The electronics were recently updated. There is a Garmin GPSMAPS 8612 xsv series 12" touchscreen IPS multifunction display chartplotter-sonar combo with BlueChart G3 and Lakeview G3. A Garmin GT56UHD-TM Traditional CHIRP High wide / UHD Clear-side transducer. A Garmin GMR Fantom 24x White 50 watt Solid State Radar, 60 RPM, 8 Bit Color, Dual Range, Overlay Support, and a Garmin Reactor 40 Hydraulic Corepack with SmartPump with GHC 50 Autopilot that has not been installed yet. Check out all the photos and call today to make it yours! Reason for selling is buying another boat.

2000 World Cat 266 SC

2000 World Cat 266 SC

Crownsville, Maryland

Make World Cat

Model 266 SC

Category Power Catamarans

Posted 1 Month Ago

Stock #400029 Walkaround in great condition! Lift kept! Perfect for family and fishing! Includes lots of upgrades! If you are in the market for a power catamaran, look no further than this 2000 World Cat 266 SC, priced right at $45,900 (offers encouraged). This boat is located in Crownsville, Maryland and is in good condition. She is also equipped with twin Yamaha engines that have 1,036 hours.

2002 Bond Yachts MC 30

2002 Bond Yachts MC 30

Crystal River, Florida

Make Bond Yachts

Model MC 30

The catamaran is in good condition for its age. It is stored out of the water on a lift. It is generally clean but could use a good wash and wax to restore its original luster. Of course, we always recommend that any buyer inspect the unit or have it surveyed independently to confirm the condition of the unit before purchase. Stock #281221 2002 BOND YACHTS MC 30 POWER CATAMARAN! TWIN SUZUKI 4 STROKES, 70 HORSEPOWER EACH! 2002 Bond Yachts MC 30 is Rare! There were only 50 hulls ever made of the MC 30 and currently there are only 12 documented in the U.S.! This is a lightweight low-fuel burn cat that has a long range. It is powered by twin 70 Suzuki four-stroke engines. At 16 MPH the fuel burn is 4 gallons an hour. It is equipped with a Mase 2.2KW diesel generator. A motor cat can be much more efficient, and hence more environmentally friendly, than a monohull of about the same length and beam. Its beach landing ramp and its ingenious bridge saloon, the MC-30 drop-down boarding ramp is brilliant! The 6' 4" headroom in the cabin makes this catamaran very comfortable with plenty of room for four to sleep! Queen bed and a double folding in the pilothouse. Custom woodwork throughout with Mahogany cabinetry! There is an enclosed head too! This is a Rare find of a Bond MC-30 in this great shape.

2007 Glacier Bay 2670 Island Runner

2007 Glacier Bay 2670 Island Runner

Panama City, Florida

Model 2670 Island Runner

The boat is in poor condition due to hurricane... has bent rail and eisenglass Kept out of water on trailer in storage. Has large 6' x 10' custom built hard top. Only ever fueled with ethanol free gas, has bottom paint, and head has never been used. Stock #131057 Cool power catamaran design, set up for extended cruising! Beautiful 2007 Glacier Bay Isle Runner Power Catamaran This 2670 Power Cat, comes with a white hull and is powered with 2007 twin 150HP Yamaha's with only 260 hours The 2670 Isle Runner offers both comfortable cruising accommodations and a stable fishing platform. Thanks to her double hulls, the 2670 can take the chop better than most boats her size. The 2670 Isle Runner has plenty of fishing features with the comfort of a cuddy cabin. The cockpit offers a generous amount of space to move around and fight a fish. A bait rigging station to starboard of the transom gate includes a freshwater sink with a handy shower nozzle. There's also a cutting board, with a convenient recessed tackle locker down below. Large under-sole insulated fish boxes feature dedicated pumpouts for easy cleanup. It's a step down into the cabin that features a queen-size berth, fresh water sink, and marine head

1994 Sea Cat SL5 2550

1994 Sea Cat SL5 2550

Make Sea Cat

Model SL5 2550

This Sea Cat has been well maintained and used very regularly. The seller has spent considerable money on rewiring, electronics, pumps, and anything that needs attention. The engines have high hours but the seller has full trust in them. Stock #381184 1994 Sea Cat. Many upgrades and newer items. Must see! 1994 Sea Cat SL5 2550 This catamaran ride will impress the most experienced boater! Rides high and smooth in good seas. The tunnel has a patented air intake that creates the experience! The seller has spent a lot of time and money ensuring this cat is reliable for his young family. The Seadek looks great and the exterior was repainted. The seller added Raymarine GPS and an autopilot to name a few of the many features that have been upgraded. The Suzuki engines have been upgraded and serviced regularly, the seller has used this boat for many offshore trips with his family and loves its dependability. The lookout above the T-top is a favored spot for the family. The Sea Cat is ready to fish with baitwells and live wells throughout. There is a sturdy aft boarding ladder for diving or shore excursions. Come check out this cat today! Reason for selling is getting another catamaran w/ a cuddy.

2002 ProKat 2860 CC

2002 ProKat 2860 CC

Baldwin, New York

Make ProKat

Model 2860 CC

This unit shows well and pride of ownership is seen throughout. The seller has updated the boat. Motors have been upgraded to 2020 model. Everything works as it should, don't wait this one, this boat will not be on the market long! Recent upgrades include: 2020 twin Evinrude 150 E-TEC HO engines installed April 2022. Low hours of 150, two newer VHF radios, AIS too! Outriggers, newer Lowrance radar, newer Lowrance 12 live chartplotter, Simrad GO12 chartplotter, Lowrance 8" chartplotter, Autopilot, EPIRB, rewired 2023, 4 new batteries 2023, updated nav lights and masthead light, PA and horn with siren. Stock #383143 2002 center console catamaran with updated canvas dodger and pilothouse canvas, twin Evinrude 150 E-TEC HO engines installed April 2022 This purple cat 2860 CC needs no introduction, it is a solid catamaran platform with 2020 Evinrude 150 E-TEC motors. This center console powercat has a porta-potty in the console. She has shore power with a newer battery charger and many upgrades throughout this boat. The current captain is a veteran boater with a captain's license and has spared no expense on this boat and is regularly offshore with her. Do not hesitate to call and discuss this vessel or put in an offer, this boat will not last long. Someone's going to get a great boat! Reason for selling is not using.

2008 Twin Vee 290CC

2008 Twin Vee 290CC

Rockport, Texas

Make Twin Vee

Model 290CC

Must see in person to appreciate the overall condition. The seller said she runs great and everything works as it should. This vessel is ready to go. The Interior and exterior look great, you can tell the owners have loved her. Stock #259965 290DC Power Catamaran powered by Twin 225HP Evinrude E-TECS! This 2008 29-foot used Twin Vee Catamaran is a great fishing boat for sale. Located in Rockport,Texas. This is an impressive power catamaran boat. Twin Vee boats are known for their phenomenal ride, the power, efficiency, and easy docking of twin motors, and quality workmanship. This Twin Vee 290 Dual Console lives up to its reputation. The Twin Vee 290 CC really is proof you can have the best of a fishing boat and a family boat all in one. Loaded with features, this 240 Dual Console is a great find! Just some of the features include the upholstery on the rear bench seat, twin helm seating with bolsters and footrests, bow seating/sun pad and bow bolsters, an easy to use boarding ladder, and fresh and saltwater washdowns. Ready to Go Fish, simply fold down the rear bench seat for a large cockpit with two tackle centers and a large live well with high-speed pickup. Leave the snap-in bow cushions at home to reveal a large foredeck casting platform. Also included is the assortment of rod holders. Powered by twin Evinrude E-ETC 225 HP engines, this Twin Vee boat can get you offshore, or to the shallows of coastal fishing, efficiently, and reliably. Regardless of the activity or destination, this 290CC has plenty of room for all your guests and all their gear.

1999 Ocean Cat 30

1999 Ocean Cat 30

Spring Hill, Florida

Make Ocean Cat

The boat does have a few small items that need repair but nothing that stops you from fishing right now. The items that need repair are: The canopy top needs tending to. The washdown down pump needs to be replaced. The windshield wiper does not work. The starboard side bait well pump does not work but may be the wiring only. A few other minor items. Of course, we always recommend that any buyer inspect the unit or have it independently surveyed to confirm its condition before purchase. Stock #343258 Power Cat with wide beam, autopilot, radar -- perfect for fishing or cruising! If you're in the market for a top-of-the-line catamaran, you'll want to consider the 1999 Ocean Cat 30. This vessel is stunning and will impress. It is aesthetically pleasing and boasts a smooth and stable ride, making it the perfect choice for those who want to enjoy the ocean views comfortably. This would have been the one to beat back in 1999! One of the standout features of the Ocean Cat 30 is its spacious deck and comfortable seating. Whether entertaining guests or relaxing with your family, this boat has plenty of room to accommodate everyone. The interior is just as impressive, with high-quality materials and finishes throughout. The cabin is spacious and comfortable, providing ample room for sleeping and relaxing in the double berth in the port hull. The boat has plenty of storage space, so you can easily store your belongings and keep the cabin clutter-free. In terms of performance, the Ocean Cat 30 is equipped with twin four-stroke Yamaha 250 engines that provide plenty of power and speed. The boat also has various modern navigational and safety equipment, including a Ray Marine remote autopilot, 3210 Garmin fishfinder-depth/ 26-mile radar with satellite weather option, a Humminbird HELIX 7 CHIRP SI GPS G2N fishfinder-chartplotter with through-hull transducers on each hull for better side imaging; even while running at high speeds. Overall, the 1999 Ocean Cat 30 is an exceptional vessel with perfect style, comfort, and performance. Whether you want to spend a relaxing day on the water or embark on an exciting adventure, this catamaran will surely exceed your expectations.

2001 Leader 200 CAT

2001 Leader 200 CAT

Crawfordville, Florida

Make Leader

Model 200 CAT

Currently, the Leader is in storage however the seller will make it available for showings as needed. Of course, we always recommend that any buyer inspect the unit or have it independently surveyed to confirm its condition before purchase. Stock #338005 2001 Leader 200 CAT with twin Yamaha outboards! Brilliant and stable design! The 2001 Leader 200 CAT is a remarkable example of catamaran engineering by the Leader Boat Company. Its beautiful design is sure to catch the eye, with sleek lines and a modern look that sets it apart from other boats. The high-quality power catamaran ride is unlike any other boat you've driven, and this Leader 200 will track and turn without any hull slip! Its advanced technology for a 2001 and twin Yamaha 70 horsepower outboard motors makes it a reliable and comfortable ride, whether on calm waters or rough seas. The cockpit is just as impressive and spacious with under gunnel rod storage, fish box/cooler in the transom, live well, and separate battery lockers! With plenty of room for six to enjoy a great day of fishing or cruising, the Leader 200 provides an unforgettable boating experience. At the helm are hydraulic steering, accessory switches, gauges, a compass, and engine controls with an ignition kill switch. The large center console has a side door that opens for dry storage. Twin captain chairs are swivel mounted on the fiberglass pedestal box that houses a live well. The T-top has an electronics box with a dry stereo box that houses an AM/FM/CD unit, a Standard VHF radio is mounted, and rocket launchers are welded in place on the frame. Two stereo speakers are mounted port and starboard. The bow has a step-up front casting platform with two storage boxes and an anchor locker. If you're looking for a vessel that offers both style and adventure, the Leader 200 is the perfect choice.

2016 Beachcat 202

2016 Beachcat 202

North Fort Myers, Florida

Make Beachcat

The Beachcat appears in good condition and maintained. Otherwise, the boat looks good. Low, low hours! Call us today to make it yours! Well maintained, ready for a new owner to enjoy! Call us today ... Stock #378982 RARE 20' Catamaran with a head, GPS, two bow fishing chairs, clean and hours! This 2016 Beachcat 20 Located in North Fort Myers, FL stands out as a versatile and enjoyable catamaran / pontoon boat, All fiberglass! Includes a head with porta-potty, and is designed for those seeking leisurely days on the water. This model reflects a combination of functionality and comfort, making it an ideal vessel for family outings or casual cruising or fishing! With a length of 20 feet, the Beachcat offers ample space for passengers to relax and soak in the surroundings. The deck layout is well-thought-out providing comfortable seating options, including plush loungers and spacious benches. Two removable pedestal seats forward, allow for a relaxing day fishing. Baitwell conveniently located behind the port seat. A great bay boat or lake boat. But very capable to head offshore for some grouper as well. The helm is equipped with user-friendly controls, ensuring ease of operation for both seasoned boaters and those new to the water. Built with quality materials, the Beachcat 20 boasts durability and longevity. Whether you're looking to anchor in a serene cove or enjoy water sports, this pontoon boat is a versatile and stylish choice for those who appreciate a blend of performance and leisure on the open water. Reason for selling is life changes.

1999 World Cat 266SF

1999 World Cat 266SF

Winterville, North Carolina

Model 266SF

The reconditioning of this boat was completed in 2023. The finish looks very clean with good reflection in the gel coat. The 200 HP Suzuki four-stroke engines have low hours. Everything works as it should, the owner confirms. Stock #384592 1999 Worldcat 266SF and trailer, 2022 twin Suzuki 200 HP motors! If you're on the lookout for a great seafaring boat that provides the platform for both fishing expeditions and family outings, here is the boat for you! This 1999 World Cat 266 SF Power Catamaran has been reconditioned and repowered! This boat is powered by twin 2022 200 HP Suzuki 4-stroke engines. With a capacity for up to 10 passengers, she provides ample space for a day on the water with family and friends. Whether you're fishing for the catch of the day or cruising along the coastline, this vessel is functional and comfortable. The World Cat 266SF is a versatile boat that excels in various water adventures, making it the ideal choice for both avid anglers and families.

2001 Carolina Skiff Sea Chaser Cat 230

2001 Carolina Skiff Sea Chaser Cat 230

Moss Point, Mississippi

Make Carolina Skiff

Model Sea Chaser Cat 230

This boat is in good condition mechanically per the seller. The seats could use reupholstering and the boat definitely needs a good detailing, but she has great bones. The hull is in very good condition with no major nicks or scratches to be seen. The trailer has been updated and is in good condition. Of course, we always recommend that any buyer inspect the unit or have it independently surveyed to confirm the unit's condition before purchase. Stock #361953 Hard to find 2001 Sea Chaser Cat 230. Newer Raymarine Electronics, Dual Axle Magic Tilt Trailer with Hydraulic Brakes She is a great running offshore fishing catamaran, stored at the owner's home and very well maintained and updated! This boat comes with a nice clean bimini T-top, lots of bow storage and casting deck, leaning post and a removable tackle storage unit. She also has an enclosed head with a porta-potty. Electronics were updated within the past 2 years. You can't beat the great performance of the Sea Chaser CAT when it comes to off-shore fishing! With two gas tanks holding 84 gallons each of fuel, you're all set for a great day of fishing! She also comes with a double axle, Magic Tilt trailer with new torsion axels, wheels, hydraulic brakes, lines and actuator, 2" ball, crank and 5k strap, all replaced in 2023. Bunks were done in 2021. Reason for selling is down sizing.

2005 Sea Cat 220

2005 Sea Cat 220

Umatilla, Florida

Overall much better than ever expected condition for a vessel dating back to 2005. The custom rebuild has in many ways given this boat a second life. Only 40 hours on the engines. Stock #368483 Updated twin fly by wire Suzuki's, comes with trailer and more! Built to endure the rigors of the sea, this vessel has a reputation for its durability and adaptability to various water activities. Measuring 22 feet in length, the Sea Cat 220 boasts a dual-hull design. The catamaran configuration enhances stability in choppy waters and offers a smoother ride. This unit has been largely redone. Installed upgrades upon its custom rebuild include the twin 175HP fly-by-wire Suzuki motors, outriggers & a downrigger, the windlass, and a Simrad go 12 autopilot control. This design has a spacious deck layout, providing ample room for lounging and accommodating a group of friends and family. The boat's layout has strategically placed seating, storage compartments, and a well-appointed console. The design caters to the demands of angling enthusiasts, offering ample rod holders, live wells, and fish boxes. Sought after by those seeking a dependable vessel for fishing trips, leisurely cruises, or water-based adventures, this boat was built above all to FISH. Reason for selling is no longer use.

2016 World Cat 320 DC

2016 World Cat 320 DC

Fort Lauderdale, Florida

Model 320 DC

The hull side gel coat did not show any excessive scratches, chips or cracks. A compound and wax would bring them back to their glory. The white gel coat has some minor wear and could use a detail. The side window needs repair to attach it back to the hull. The exterior cushions have some split seams and cracking. The seller is currently working on the AC and hot water heater. The engine cowls and midsections look great with no damage. The lower units show some fouling, and the props should be cleaned. Stock #362210 2016 WORLD CAT 320 DC POWER CATAMARAN!!! YAMAHA 300 OUTBOARDS ONLY 20 HOURS!!! This massive World Cat is quite the cruiser. It is equipped with twin 2022 Yamaha 300 horsepower engines. The engines have low hours of less than 20, so you can expect years of service life. The bow area has plenty of room for guests. Two large lounge seats on either side and filler cushions that can be used, to make this into a massive sun longer. The huge front windshield is easily walked through or closed up for protection from the elements. The full beam hardtop provides plenty of cover. For entertainment, a tv drops down from the port side. The port side has air-conditioned cabin with a double berth. There is also a TV, stereo and microwave. The starboard side has a wet head, with a fold down seat for comfort. The captain has a neat well laid-out helm. The massive Garmin provides most information and the Yamaha LCD display engine functions. There is a Fusion stereo unit for entertainment. The port side has two seats with moveable backrests. They can be converted to make a large sun pad in the shade. For convenience, you can cook a meal. There is an outdoor grill, sink, built-in cooler and refrigerator. The cockpit has built-in bench seat, side door and door to walk out to the dive ladder.

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Vessel summary, new power catamaran for sale bali 4.4 open space boat as a business program 2024 bali catamarans bali 4.4.



Basic summary.

Boat Length: 42 ft
Asking Price: Price on Application
Type of Yacht:
Boat Condition:  
Boat Status:  
Model Year:  


Manuf. Length: 45' 1" ( 13.74 m)
Maximum Draft: 3' 9" ( 1.14 m)
Beam: 24' 3" ( 7.39 m)
LWL: 42' 6" ( 12.95 m)
Fuel Capacity: 211 g
Water Capacity: 211 g
Holding Tank: 3x55L
Weight Displacement: 19.6 ton (39200 lb)


Hull Material: Fiberglass Reinforced Plastic- FRP
Hull Configuration: Catamaran

New Power Catamaran for Sale 2024 Bali 4.4 Boat Highlights

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  •  Contact Broker Terry Grover
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Boat Description

The Company offers the details of this vessel in good faith but cannot guarantee or warrant the accuracy of this information nor warrant the condition of the vessel. A buyer should instruct his agents, or his surveyors to investigate such details as the buyer desired validated. This vessel is offered subject to prior sale, price change, or withdrawal without notice. Photos may not properly reflect the current condition of the actual vessel offered for sale. In some cases stock photographs may have been used.

Mechanical Disclaimer

Engine and generator hours are as of the date of the original listing and are a representation of what the listing broker is told by the owner and/or actual reading of the engine hour meters. The broker cannot guarantee the true hours. It is the responsibility of the purchaser and/or his agent to verify engine hours, warranties implied or otherwise and major overhauls as well as all other representations noted on the listing.

Dinghy Disclaimer

All dinghies are considered separate vessels and should have separate titles and documents. There is no guarantee as to the title of the dinghy on this vessel so Buyer accepts that while he may receive the dinghy included in the transaction, he may not receive the proper title to it.

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sunreef second sunreef 100 power catamaran yacht launched

Second Sunreef 100 Sunreef Power catamaran hits the water

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Polish catamaran specialist Sunreef Yachts has announced the launch of its second 28.6-metre 100 Sunreef Power.

The first hull was delivered in 2021 and is the largest power catamaran to be built by the shipyard to date at 29.5 metres in length. Hull number two is described by Sunreef as an "ultramodern catamaran" and will feature the same "unrivalled living space" as its sistership. 

The yacht, which is designed in-house, will feature a custom layout with accommodation for up to 12 guests across six cabins including a master suite positioned forward on the main deck with direct access to the full-beam bow terrace. The main deck will also play host to a central dining and lounging area as well as a custom drinks bar.

Other custom features on board the new 100 Sunreef Power will include an enclosed lounge area on the flybridge at the owner's request. This will house an enclosed cigar lounge boasting a bar, expansive 85-inch TV and lounging sofas.

Like its sistership, the second hull will have a hydraulic swim platform that doubles as a launchpad for the tender, alongside a garage that accommodates two Jet Skis with room for additional water toys.

Power will come from a pair of 1300hp engines and the 100 Sunreef Power will have "transatlantic autonomy".

The 100 Sunreef Power is the second largest model in the shipyard's range of power catamarans, second only to the 49-metre Sunreef Power which is currently under construction in Gdansk, Poland.

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experiment unit 731

experiment unit 731


Inside Unit 731, Japan's Gruesome WWII Human Experiment Program

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unit 731

Key Takeaways

  • Unit 731, a Japanese Imperial Army program, conducted deadly medical experiments and biological weapons testing on Chinese civilians during WWII.
  • Thousands of prisoners were killed in cruel experiments, and perhaps hundreds of thousands more died from biological weapons testing.
  • The true extent of Unit 731's actions was shielded from public knowledge for years, with the U.S. granting immunity to top officials in exchange for research.

For years after World War II , in most of what was considered the "civilized" world, the truth behind Japanese Imperial Army Unit 731 was quietly swept away. Facts were suppressed. Memories questioned. Reports denied.

Even today, the true extent of Unit 731's wartime actions — horrendous, deadly medical experiments and lethal biological weapons testing on unsuspecting Chinese civilians — is known largely only to historians and scholars.

But the facts are out there for those who seek them. And for those who seek to use them for their own personal reasons.

"I think that it has become a piece of this tortured dialogue over the war between Japan and China. The Chinese have seized upon this quite a bit. And the Japanese right, the nationalist right, their basic view is that, 'Oh, the Chinese. This is all political.' ... And there is a certain truth to that," says Daniel Sneider , a lecturer in international policy at Stanford's Freeman Spogli Institute for International Studies . "There is a 'uses of the past' question here. Perhaps you could say it's cynical in that everybody does it."

The truth is that Japan's Unit 731 committed some of the most heinous war crimes ever. Thousands of prisoners were killed in cruel human experiments at Unit 731, which was based near the northeastern China city of Harbin, north of the Korean peninsula and on a border with Russia. Perhaps hundreds of thousands more — maybe as many as a half-million — were killed when the Japanese tested their biological weapons on Chinese civilians.

The exact number of dead is not known. It may never be known.

"It's very difficult to calculate," says Yue-Him Tam , a history professor at Minnesota's Macalester College and co-author of a book entitled, " Unit 731: Laboratory of the Devil, Auschwitz of the East (Japanese Biological Warfare in China 1933-1945) ." Tam, born and raised in China, has taught a class at Macalester on war crimes and memory in contemporary East Asia for more than 20 years. "If you include those victims who suffered from the other activities — not necessarily just used as human guinea pigs — the bombs in China ... it's very difficult to calculate."

unit 731

The Start of Unit 731

America's shameful part, dealing with unit 731 today.

Unit 731 — its official name was the Epidemic Prevention and Water Purification Department of the Kwantung Army — was formed before World War II began (at least for the U.S., which didn't officially enter the war until December 1941). It came about sometime in the mid-1930s when Japan and China went to war , a conflict that eventually morphed into World War II's war in the Pacific theater.

The Unit's charge was clear from the beginning: testing, producing and storing biological weapons. Such activities were outlawed by at least two international treaties at the time, though the Japanese did not ratify the 1925 Geneva protocol . It didn't matter.

From the start, Unit 731, under General Shirō Ishii , was merciless.

Among the thousands of experiments conducted on prisoners: vivisections without anesthesia; injections of venereal diseases to examine their spread; amputations to study blood loss; removal of other body parts and organs; starvation; and deliberate exposure to freezing temperatures to examine the effects of frostbite . From a 1995 article in The New York Times , relating a story from a medical assistant in Unit 731:

Reportedly, not one of the thousands of prisoners that were experimented on — most of whom were Chinese, though many were Russian or Korean — survived.

Later, the Japanese took especially virulent forms of the plague and other pathogens that were developed at Unit 731, put them in canisters and dropped them on nearby towns to see if their weapons would work. They did.

Thousands of these still-dangerous bombs remain in the Chinese countryside today, Tam says. Some people still suffer from the Japanese "dirty" bombs.

At one time, the Japanese hatched a plan to infect fleas with a plague manufactured at Unit 731 and drop flea-filled bombs, launched from planes stored aboard submarines, on San Diego in a mission code-named Operations Cherry Blossoms at Night . The war ended before the plan could be executed.

After the U.S. dropped atomic bombs on Japan and effectively ended the war in 1945, Japanese leaders ordered the destruction of Unit 731, which included more than 150 buildings and two airports. As the victorious Allied forces approached, many hundreds of remaining prisoners were killed. The thousands of people who worked in the place and conducted experiments on healthy, living humans scattered, many never to face justice.

unit 731

The top doctors and soldiers at Unit 731 kept careful records of their experiments, and used them to leverage their way to freedom after the war. When the Allies swept into China, they agreed to grant Ishii and many of his associates immunity from prosecution for war crimes . The reasons: The U.S. wanted Unit 731's research for its own use , and it wanted to keep that information out of the hands of others, including the Russians. Thus, for years, the true nature of what went on in Unit 731 was shielded from public knowledge.

Some of the truth came out in the Khabarovsk War Crimes Trial , held in that Russian city in December 1949. Twelve members of Unit 731 and associated units were tried. All were found guilty and imprisoned. Despite that trial, though, much of what went on in Harbin was immediately classified by the U.S. government and remained clouded in secrecy.

More details about Unit 731 are still being unearthed. A confession from a unit commander, written to U.S. interrogators at a base in Maryland shortly after the war, was released in August 2021 by a Chinese provincial agency. Chinese and Russian news outlets heralded the release, which highlighted America's part in using the information gathered by Unit 731, hiding it and protecting its sources from further prosecution.

"The United States is not the outsider to this. Previously, I think the tendency was for the people in the United States to think, 'This is a problem between Japan and its neighbors.' But not only were we of course the major combatant in the war, we shaped the postwar settlement, including decisions like the one concerning Unit 731," Sneider says. "We made the big decisions about what was a war crime and what wasn't ... We're the creator of the postwar order, and therefore we have responsibility and involvement in dealing with the issues that were left, unfortunately, unresolved."

unit 731

Research on 731 continues to be conducted all over the world. As recently as 2018, the Japanese government provided a list of more than 3,600 members of Unit 731 to a Japanese scholar. Yet even with more information, with politicians and the governments of various countries opening their records, the facts remain largely in the shadows and in some dispute.

In China, with the resurgent government now not as dependent on Japan as it was in the years following World War II, the Chinese are demanding more answers, eager to hold old rival Japan responsible.

For their part, most Japanese are not nearly as willing to engage in discussions about what is considered by many Japanese as a shameful period in that country's history. Some say the surge in Chinese interest in Unit 731 is nothing more than political in nature.

The U.S. is dealing with its own internal demons about its history with Unit 731.

These varying viewpoints, and others in the region and throughout the world, complicate matters. From 2006 to 2016, Sneider and others at Stanford's Walter H. Shorenstein Asia-Pacific Research Center conducted a project, " Divided Memories and Reconciliation ," aimed at examining the historical memory of the wartime period in Asia. These histories, viewed differently, go directly to ideas about national identity and nationalism. They are tricky histories to examine, uncovering differences that often stay unresolved.

"Sometimes the truth is pretty elusive," says Sneider. "To some degree, the goal is not necessarily always to establish 'the fact.' That's a good goal, but it may not be possible. The goal, if you're seeking reconciliation, the goal may be to understand the different perceptions of the other.

"In Japan, wartime memory is highly contested within Japan. They've been battling over these issues since 1945. Sometimes it's important just for Koreans and Chinese and Americans to understand what's going on within Japan. That path is contrived; to try to get to reconciliation by agreeing on what happened."

People may not agree on how many people were killed by the criminals in Unit 731, who did it, how it was done, or why it occurred. They can, and should, look critically upon America's decisions after the war, too.

But this much is indisputable: What happened in Unit 731 was an abomination.

In August 2015, The Museum of Evidence of War Crimes by Japanese Army Unit 731 opened in an area just south of Harbin, a city of more than 5 million people. Tam is among the millions who have visited the site.

"The room where they experimented with poisonous gas, there are still walls standing there, and the walls are really thick, almost like 1-meter [3.2-feet] thick, to prevent leaking of something. When I saw these things, I was really shedding tears as to how people can do that," Tam says. "It was very moving.

"I am a historian. The most important thing that matters to me is the facts. I want to find out the facts. And that was a fact, Unit 731. The crimes they committed and produced are facts."

General Shirō Ishii

Japanese war criminals were tried at the International Military Tribunal for the Far East , otherwise known as the Tokyo War Crimes trial. Testimony from Ishii , gathered in Maryland after his postwar arrest, was used in the trial, too. But Ishii, the architect behind the Unit 731 atrocities, was never charged. He died in Tokyo in 1959, a free man.

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experiment unit 731

Japan’s Hellish Unit 731

In conquered Manchuria, ghastly experiments were fiendishly conducted on human guinea pigs.

This article appears in: Fall 2018

By David D. Barrett

The final months of World War II saw the liberation of hundreds of ghastly concentration camps and the awful reality of Nazi racism. For more than seven decades those atrocities, including the use of human beings for medical experiments, have been common knowledge. Far less known is the wholesale slaughter of hundreds of thousands of Chinese by a Japanese organization known as Unit 731.

Established for the purpose of developing biological and chemical weapons, Unit 731 exceeded by a year the duration of the Third Reich. While biological and chemical weapons were not new to warfare, Japanese testing on human subjects was unparalleled even by the Nazis.

What makes this descent into barbarity all the more stunning was the Japanese contribution to medical science just three decades earlier. A U.S. Army doctor named Lewis Livingston Seaman observed colleagues who were attending to the Imperial Japanese Army (IJA) during the Russo-Japanese War (1904-1905).

Dr. Seaman came away from his experience profoundly impressed with his medical brethren, stating, “The history of warfare for centuries has proven that in prolonged campaigns the first, or actual enemy, kills 20 percent of the total mortality in the conflict, whilst the second, or silent enemy (disease), kills 80 percent.

“I unhesitatingly assert that the greatest conquest of Japan has been in the humanities of war, in the stopping of the needless sacrifice of life through preventable disease. Japan is the first country in the world to recognize that the greatest enemy in war is not the opposing army, but a foe more treacherous and dangerous—preventable disease, as found lurking in every camp—whose fatalities in every great war of history have numbered from four to twenty times as many as those of mines, bullets, and shells.

“It is against this enemy that Japan, with triumphant exaltation, may cry Banzai. For it is against this enemy that she has attained her most signal victories….”

Twenty years later, Japan signed the Geneva Convention, which prohibited biological and chemical warfare. But where other men reasoned with justification that these kinds of weapons should be banned by civilized nations, another man, a specialist in bacteria and related fields, Dr. (Colonel) Shiro Ishii, saw the prohibition as an opportunity.

He reasoned that if something were bad enough to be outlawed, then it must certainly be effective, and he began a sustained effort to establish a military arm within the Japanese Army whose aim would be the development of weapons based on biology. Ishii was highly intelligent but arrogant, merciless, and immoral.

He thought of himself beyond reproach and as a visionary. He was driven to break new scientific ground and to help Japan defeat its foes. In his quest to contribute to that effort, Ishii in time exhorted his team of physicians to violate the physicians’ ethical code: “A doctor’s God-given mission is to challenge all varieties of disease-causing micro-organisms; to block all roads of intrusion into the human body; to annihilate all foreign matter resident in our bodies; and to devise the most expeditious treatment possible….

“However, the research we are now about to embark is the complete opposite of these principles, and may cause us some anguish as doctors. We pursue this research for the double medical thrill; as a scientist … probing to discover the truth in natural science; and as a military person, to build a powerful military weapon against the enemy.”

To convince the senior levels of the Imperial Army to back his efforts, Ishii built his case around financial considerations, completely skirting either Japan’s obligation to the world community as a signatory of the aforementioned 1925 Geneva Convention or the morality of using such weapons. Ishii argued that compared with the costs of building, manning, and maintaining huge conventional forces, bacteria and gas were a far less expensive alternative.

Japanese soldiers guard Chinese prisoners during the invasion of Manchuria, September 1931. Many prisoners of war, as well as civilians, were used as subjects in the horrific experiments.

By 1930, nationalism burned hotter than ever in Japan and created a climate receptive to Ishii’s ideas of developing biological weapons. In September 1931, Japanese forces instigated the “Mukden Incident.” The pitched battle between Japanese and Chinese forces was actually no more than a Japanese ruse used to justify a complete takeover of Manchuria.

Moreover, the area became the perfect place to develop and test Ishii’s new biological and chemical weapons, a place where he would be free to conduct any kind of experiment he deemed beneficial.

The following year, under the cover of the euphemistically named Epidemic Prevention Research Laboratory, Ishii set up shop in the Army’s hospital in Tokyo. The location was only temporary because, to accomplish his objectives, he would need access to far greater resources; Japanese ascendancy in Manchuria provided its medical community unprecedented opportunities for research (much as the Germans used concentration camps and their prisoners for their own medical and pseudo-scientific research).

Ishii’s goal of turning bacteria and gas into weapons for the Imperial Japanese Army required comprehensive study, and he believed animals could not supply usable data. Japan’s control over Manchuria delivered research materials in the form of people who were plucked from the streets and locked into black vans known as voronki (ravens), to be carried off to the waiting prison cells of Unit 731.

Japan’s Kempeitai, the military police arm of the IJA from 1881 to 1945, was tasked with these kidnappings. The Kempeitai was less a conventional military police body than a secret police force akin to the Gestapo. Headed in Manchuria by Hideki Tojo, from 1935 to 1937, the Kempeitai’s cruelty was notorious in occupied territories. (See WWII Quarterly, Fall 2011). After the war, the U.S. Army estimated it numbered 36,000 regular members.

Anxious to take operations to the next level, in 1932 Dr. Ishii chose the city of Harbin, capital of Heilongjiang Province in southwest Manchuria, as the site of Unit 731’s first biological and chemical weapons facility. The original buildout covered a 500-square-meter area and was designated a restricted military zone. A tract of land to the south of the sector was appropriated and made into an airport. It and a nearby rail line were also used to move victims to Unit 731 and transport results and specimens back to Japan’s medical community.

Japan’s medical institutions enabled the work of Unit 731 by supplying Dr. Ishii with top Japanese scientists and physicians who would be labeled Hikokumin (traitors) if they refused to take part. Most medical professionals saw their work as noble service to the Emperor; the fact that they were killing non-Japanese meant nothing to them.

Unit 731 received state-of-the-art equipment and a nearly unlimited supply of funds from the Japanese government. Even for reluctant researchers Ishii’s factories were luxurious. The annual budget for Unit 731 was ten million yen (about nine billion yen in the modern currency, or about $86 million). Salaries were very generous, and the food was exceptional.

Precipitated by an escape attempt by 40 prisoners, all of whom were captured and killed, the Harbin operation was closed and moved to the Harbin suburb of Ping Fang in 1936. This complex was a sprawling walled city of more than 70 buildings that dwarfed its predecessor in Harbin. The perimeter at Ping Fang incorporated more than six square kilometers and rivaled Auschwitz-Birkenau in size. Tucked away inside the administration building was a prison that housed 500 men, women, and children selected for vivisection.

As immense as Ping Fang was, Unit 731 also had affiliated locations in Nanking (Unit 1644), Beijing (Unit 1855), and Changchun (Unit 100). Altogether there were 26 known killing laboratories, experimental detachments, and battalions of the Army spread across occupied lands in Asia. The total number of personnel involved reached some 20,000. All units and facilities were coordinated by the Epidemic Prevention Research Laboratory under the control of Colonel Ishii.

The research was made available not just to the Army hospital in Manchuria, but to doctors and educators throughout Japan. In this way, Unit 731 was performing the service of human experimentation for the entire Japanese medical community, in an on-going feedback loop. “Medicine itself must become a weapon,” said Nakagawa Yonezo, Professor Emeritus at Osaka University.

The gruesome professionalism of Unit 731 included a touch of sardonic humor. The construction of the Ping Fang installation prompted locals to ask what it was. The answer was a “lumber mill.” Regarding this reply, one of the researchers joked privately, “and the people are the logs.”

Chinese children were subjected to plaque-prevention experiments by Unit 731. Other experiments involved typhus, anthrax, cholera, TB, encephalitis, and more.

From then on, the Japanese term for log, Maruta, was used to speak of the prisoners whose last days were spent being infected with lethal pathogens, torn apart, frozen, or gassed by Japanese researchers. The expression indicates a degree of racism far beyond disdain; it is evidence of a belief that torturing the Chinese was of no more consequence than squashing a bug.

As noted earlier, the primary objective of Ishii and Unit 731 was the creation of biological and chemical weapons. To facilitate that end, wholesale human experimentation was utilized, including the vivisection of thousands of people. The justification for performing all these surgeries came from the expectation that human tests would create better weapons.

Doctors in Unit 731 examined the first stages of disease on organs. A former member of Unit 731 described the process: “As soon as symptoms were observed, the prisoners were taken from their cells and into the dissection room, he was stripped and placed on a table, screaming, trying to fight back. He was strapped down, still screaming frightfully. One of the doctors stuffed a towel into his mouth, then with one quick slice of the scalpel he was opened up.” Witnesses reported that, without anesthesia, the victims let out horrible screams when the first cut was made and that the cries stopped soon thereafter.

A doctor at Ping Fang testified to a time when he was working on a pregnant female victim who awoke from anesthesia while being vivisected. The woman said, “It’s all right to kill me, but please spare my child’s life.” It is likely that more than one mother voiced, as a last wish on the vivisection table, the wish to let her child live. None ever did. The researchers wanted their data.

As ghastly as these procedures were, vivisections were not limited to weapons development, but fell into four categories: (1) intentional infection of diseases, (2) training newly employed army surgeons, (3) trials of nonstandardized treatments, and (4) discovering the limits of human tolerance to pain and stress.

Under the auspices of weapons development and intentional infection of diseases, prisoners were injected with various biological agents including plague, typhus, cholera, anthrax, and syphilis.

To test the effectiveness of dispersion methods for military purposes, victims were staked to crosses with their vital organs and heads protected. Various types of bombs and agents were then dropped or sprayed from specially modified planes to test the survivability of the agents and their ability to infect the subjects. Community water and food sources were also contaminated. To determine the results, mobile vivisection units were set up in the field near the infected communities.

The Imperial Japanese Army also allowed its physicians to perform vivisections on living subjects to train them in the treatment of battle wounds—procedures that are too gruesome to describe in detail.

Tests that could have real medical value were also conducted, such as finding the best method to deal with frostbite. But even here Japanese doctors chose to perform the experiments in the most merciless ways possible.

Conventional weapons tests were also carried out. Victims were tied to stakes and used to determine the operational range of flamethrowers, grenades, and various kinds of shells and bombs.

Japanese microbiologist Dr. Shiro Ishii, head of Unit 731.

But this was hardly the extent of the tests to which the prisoners were subjected. Sheldon Harris, author of Factories of Death, stated, “They just killed people with no inherent purpose other than to see how they reacted to being killed.” People were locked into high-pressure chambers until their eyes popped out, or they were put into centrifuges and spun to death.

Other experiments involved hanging prisoners upside down to discover how long it took for them to choke to death or injecting air into their arteries to test for the onset of embolisms. Another test consisted of taking blood samples, at least 500 cm³ (slightly more than a pint) at two- to three-day intervals. Some victims became debilitated; still, the blood drainage continued.

When the human guinea pigs could no longer serve as lab material, they were abused in various manners: injected with poison, killed for their vital organs (brains, lungs, or liver), subjected to violent surgeries (e.g., amputation and reattachment of the limbs to the opposite sides of the body, resection of the stomach to attach the esophagus to the intestines). Electrical shocks were administered until the person slowly roasted to death.

Some experiments had no medical purpose whatsoever except the administering of indescribable pain, such as injecting horse urine into prisoners’ kidneys. The doctors of Unit 731, like the Nazi doctors at Dachau and Buchenwald, indulged any perversion they could imagine.

In 1938 and 1939, the Soviet and Japanese Armies clashed in two encounters near the border of Mongolia and Manchuria. The 1939 summer battle, known as the Nomonhan Incident and the Battle of Kalhin Gol by the Soviets, resulted in the overwhelming defeat of the Japanese Kwantung Army by Stalin’s Red Army.

The clash saw the first field operation of Japan’s biological warfare unit; it occurred in a desert region where water was scarce. To disable their Russian foes, the Japanese dumped large quantities of intestinal typhoid bacteria into the river.

Fortunately for the Russians, this type of typhoid germ became ineffective almost immediately after hitting the water. The contamination was probably initiated more for the publicity than anything else, as Ishii likely knew it would not work.

In 1940, Japanese planes dropped wheat, corn, rags, and cotton infested with bubonic plague on the unarmed village of Ningbo, China. More than 100 people died within a few days of the attack.

Two years later, the Japanese conducted a second attack in the same area. Japanese researchers took over a house on top of a hill about a kilometer away from the infected zone to use as a vivisection laboratory. As a result of the attacks, the Ningbo region remained sealed off until the 1960s.

During the siege of Bataan in the Philippines in March 1942, the Japanese planned to release 200 pounds of plague-carrying fleas—about 150 million insects—in each of 10 separate attacks. However, by the time the assault was ready the battle had already ended.

In June-July 1944, during the Battle of Saipan, plague-infested fleas were again to be used against U.S. forces. Fortuitously for the Americans, by this stage in the war it had become almost impossible for the Japanese to get any reinforcements and or matériel to its island bastions, and the Japanese submarine carrying the fleas was sunk en route.

For the Battle of Iwo Jima, February-March 1945, another biological attack was to be carried out against the invading Americans. Two gliders loaded with pathogens were to be towed over the battlefield and released. The gliders never reached their destination.

Japan employed 9,000 incendiary balloon bombs, known as fugo, in an attempt to bombard North America. Biological attacks on California were planned but never carried out.

One of the least known Japanese efforts to attack Canada and the continental United States occurred in late 1944 and the spring of 1945. Records uncovered in Japan after the war indicated that about 9,000 balloon bombs, known as fugo, and carrying incendiary bombs, were launched into the jet stream during this period. More than 200 ultimately reached the United States. Six people were killed in Oregon when a bomb detonated on discovery. Before Japan surrendered, Ishii and Army leaders proposed using balloon bombs filled with cattle plague and anthrax.

As part of Japan’s defense of Okinawa in the spring of 1945, Unit 731 had developed plans to meet the American invaders with plague bacteria. The attacks were never carried out because once again fleas carrying the plague could not be delivered to the island. The native Okinawan population only learned of this plan in 1994.

Operation PX, aka Cherry Blossoms at Night, were the codenames for the Japanese plan for a biological attack on cities in southern California. The plan was completed March 26, 1945, and scheduled for September 22, 1945, but was abandoned due to the strong opposition of Army Chief of Staff General Yoshijiro Umezu, who was also a member of Prime Minister Suzuki’s war cabinet.

The plan involved the use of five I-400 submarine aircraft carriers, each carrying three Aichi M6A Seiran floatplanes launched against San Diego, Los Angeles, and/or San Francisco. The aircraft were to spread bubonic plague, cholera, typhus, and dengue fever over the city, while the submarine crews infected themselves and ran ashore in a vast suicide mission.

Even after surrender, the Japanese considered a final use of biological weapons. Ishii wanted to stage suicide germ attacks against occupying U.S. troops in Japan. This planned attack never took place, once again due to opposition from General Umezu and Vice Chief of the Imperial Japanese Army General Staff, General Torashiro Kawabe, who claimed that he did not want Ishii to die in a suicide attack.

Almost as soon at World War II ended, a new Cold War began between the United States and the Soviet Union. In this atmosphere, Lt. Col. Murray Sanders of the United States Army recommended to General Douglas MacArthur and President Harry Truman in the fall of 1945 that Ishii and his subordinates be given immunity from prosecution as war criminals in return for Unit 731’s research.

MacArthur and Truman approved the deal, and Japan’s biological and chemical weapons program remained largely a secret until the 1990s.

From start to finish, the highest levels of the Japanese government and military were involved in Unit 731. Hideki Tojo, head of the Kempeitai in Manchuria from 1935 to 1937, became Japan’s longest serving prime minister in World War II, from October 18, 1941, to July 22, 1944. Tojo approved the attack on Pearl Harbor and was tried as a Class A war criminal and hanged in 1948.

General Yoshijiro Umezu, who served as the Army’s chief of staff, was a member of the elite war cabinet that held the reins of power in Japan from April 1945 until it surrendered to Allied forces on September 2, 1945. According to Lt. Gen. Kajitsuka Ryuji of the Japanese Medical Service and former Chief of the Medical Administration for the massive Kwantung Army (located in Manchuria), Ishii was given permission to begin the Ping Fang experiment in 1936 by “command of the Emperor.”

At some point in 1939-1940, Hirohito issued still another decree recognizing Ishii’s unit for its service. Moreover, the Emperor’s younger brother toured Unit 731’s facilities during its time of operation.

Unit 731 was extremely well funded, with state-of-the-art facilities, generously staffed with the cream of Japan’s medical community, and routinely communicated with the medical establishment back in Japan—which even provided suggestions for experiments and regularly received human samples.

The vast majority of Ishii’s staff walked away from their wartime service scot free. Information turned over to the United States proved worthless to the American biological weapons program, as the vivisection of human beings did not yield better scientific data.

A recent photo of fog-shrouded building on the site of the Unit 731 bioweapon facility at Ping Fang. Today it is part of a museum and memorial to the victims.

Immune from prosecution as war criminals, many of Unit 731’s doctors went on to prominent careers in universities, hospitals, and industry, rising to positions that included governor of Tokyo, president of the Japanese Medical Association, and head of the Japanese Olympic Committee. The ringleader, Dr. Shiro Ishii, quietly returned to private practice and died in 1959 of throat cancer at the age of 67.

The Soviet Union was the only government to bring anyone associated with Unit 731 to trial. In late December 1949, in Khabarovsk, Russia, 12 former physicians, officers, and staff were accused of manufacturing biological and chemical weapons. While there was some coverage in the American press, the United States government, keen on protecting its secret deal, labeled the proceedings just another Soviet show trial.

It would take nearly 50 years before the infamy of Unit 731 came to light in the United States. Unlike the Nuremberg and Tokyo trials, in which high-ranking German and Japanese officials were hanged or sentenced to life in prison, the Khabarovsk trials saw no sentence exceed 25 years—with some as short as two. All of the defendants were quietly freed and slipped back to Japan by 1956.

In 1998, more than 100 Chinese plaintiffs filed suit in Japan in an effort to get the Japanese government to acknowledge the crimes of Unit 731 and to obtain reparations for the victims and their families. Mere months before the trial began, the Japanese Education Ministry approved a textbook glossing over the Imperial Japanese Army’s culpability.

The Tokyo District Court’s ruling, coming on August 28, 2002, accepted that Unit 731 had waged germ warfare in China and caused harm to residents but dismissed the Chinese plaintiffs’ claim for compensation. Nevertheless, it was the first time a Japanese court admitted that the Imperial Army had used biological weapons during its war with China from 1932-1945.

Judge Iwata said in handing down the ruling, “The evidence shows that Japanese troops, including those from Unit 731, used bacteriological weapons under the order of the Imperial Japanese Army’s headquarters and that many local residents died.” Noteworthy in the judge’s declaration was his understatement that “many local residents died.”

The judge’s comment was, however, consistent with much of the narrative written about Unit 731 after the war, which generally characterizes the group’s activities as “experimental,” a seeming reference to the vivisections conducted by the Japanese doctors.

Most accounts reckon the loss of life caused by vivisection to be around 3,000 to 10,000 individuals. These figures neglect the field tests of pathogens conducted against Chinese civilians and the subsequent losses of life from bubonic plague after the war.

Such minimization constitutes a miscarriage of justice for the hundreds of thousands who were murdered as a result of these attacks, and potentially the tens of thousands more Americans who could have died if the Japanese plans had been carried out on numerous Pacific battlefields, or if they had been successful in their attempts to deliver biological agents to the U.S. mainland in the latter stages of the war.

As it stands, Sheldon Harris’s Factories of Death (1994) estimates the loss of life at 200,000, with Daniel Barenblatt’s A Plague Upon Humanity (2008) putting it as high as 580,000.

At what point is Unit 731 indicted for mass murder? While some Japanese scholars have been rigorous in documenting Japan’s war crimes, their own government has been unwilling to acknowledge the atrocities it perpetrated against China.

Unit 731’s legacy is one of a useless, fanciful, extravagant, and sadistic indulgence that accomplished nothing politically or militarily for Japan, and, in terms of its research, nothing for the United States.

One can only hope that the perpetrators, who escaped prosecution as war criminals, achieved something positive in their postwar careers because the victims are still crying out for justice.

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Unit 731

The Unit 731 complex. Two prisons are hidden in the center of the main building.

LocationPingfang, Harbin, Heilungkiang, Manchukuo
Coordinates45°36′30″N 126°37′55″E
Attack typeHuman experimentation
Biological warfare
Chemical warfare
Weapon(s)Biological weapons
Chemical weapons
DeathsEstimated 200,000 (Kristof 1995) or 300,000 (Watts 2002)–400,000 or higher from biological warfare
Over 3,000 from inside experiments (not including branches, 1940–1945 only) (USSR 1950)
At least 10,000 prisoners died
Perpetrator(s)Surgeon General Shirō Ishii
Lt. General Masaji Kitano
Epidemic Prevention and Water Purification Department

Unit 731 , short for Manshu Detachment 731 , was a unit of the Imperial Japanese Army that engaged in unethical and deadly human experimentation , including testing of biological and chemical weapons on human populations, during the Second Sino-Japanese War (1937–1945) and World War II . Based in Japanese-occupied China , it was responsible for some of the most notorious war crimes committed by the armed forces of Imperial Japan, including anthrax, cholera , and bubonic plague attacks on both military and civilian populations; vivisection of men, women, children, and infants (often without anesthesia); testing of grenades and flamethrowers on people; and subjecting victims to water deprivation, low pressure, low temperature (causing frostbite), chemical agents, amputation and limb reattachment, being buried alive, and other atrocities. Because Shirō Ishii was director of Unit 731, the division has also been referred to as the Ishii Unit.

  • 2.1 Zhongma Fortress
  • 2.2 Unit 731
  • 2.3 Other units
  • 3.1 Chemical agents and chemical weapons
  • 3.2 Biological agents and biological weapons
  • 3.3 Frostbite testing
  • 3.4 Vivisection
  • 3.5 Venereal diseases
  • 3.6 Weapon testing
  • 3.7 Other experiments
  • 4 Victims, including numbers of victims
  • 5 Known unit members
  • 6 Divisions
  • 7 Facilities
  • 8.1 Destruction of evidence and arrest
  • 8.2 American grant of immunity
  • 8.3 Separate Soviet trials
  • 8.4 Aftermath
  • 10 References

The heinous acts of torture committed by Unit 731 mirrored the inhumane experimentation conducted on prisoners by Nazi Germany. However, the aftermath of the two atrocities were very different. Many of the perpetrators of the Nazi human experimentation were tried by the United States in the Doctors' Trial , and the response to the unveiling of the Nazi crimes included the pivotal development of the Nuremberg Code and subsequently other sets of ethical standards for research with human subjects. In the case of Unit 731, most of the key participants in Unit 731, including Shirō Ishii, escaped prosecution via an agreement with the United States to provide their research findings. In addition, most of the Unit 731 crimes escaped public attention for years. Some of those responsible for Unit 731 were captured by the Soviet Union and subject to trials by that nation.

Unit 731 was active in Japanese-occupied territory in Asia, notably Manchuria . The Empire of Japan first invaded Manchuria in 1931, and in 1932 established the puppet state of Manchukuo. The formation of Unit 731 began in 1932 with the establishment of a research group in Manchukuo for chemical and biological experimentation.

Japan occupied other areas in Asia during the Second Sino-Japanese War and the Second World War and established branch offices of Unit 731 in some of these areas as well. The Second Sino-Japanese War (1937–1945) was primarily waged between the Republic of China (1912–1949) and the Empire of Japan. The beginning of the war is conventionally dated to the Marco Polo Bridge Incident on July 7, 1937, when a dispute between Japanese and Chinese troops in Beijing escalated into a full-scale invasion. This full-scale war between the Chinese and the Empire of Japan is often regarded as the beginning of World War II in Asia: after the Japanese invasion of Malaya and attack on Pearl Harbor in 1941, the Second Sino-Japanese War merged with other conflicts that are generally categorized under those conflicts of World War II. However, some scholars consider the European theatre of World War II and the Pacific War to be entirely separate, albeit concurrent, wars. Other scholars consider the start of the full-scale Second Sino-Japanese War in 1937 to have been the beginning of World War II. Following the Marco Polo Bridge Incident, the Japanese scored major victories, capturing Beijing, Shanghai, and the Chinese capital of Nanjing in 1937. After failing to stop the Japanese in the Battle of Wuhan, the Chinese central government was relocated to Chongqing (Chungking) in the Chinese interior.

The formation of Unit 731 traces to 1932, when Surgeon General Shirō Ishii, chief medical officer of the Imperial Japanese Army, organized a secret research group, the "Tōgō Unit," for chemical and biological experimentation in Manchuria. In 1936, Emperor Hirohito authorized the expansion of this unit and its integration into the Kwantung Army as the Epidemic Prevention Department (Barenblatt 2005). In 1940, it became known as the Epidemic Prevention and Water Purification Department of the Kwantung Army (Tanaka 1996), or Unit 731 ( 731部隊 , Nana-san-ichi Butai ) , short for Manshu Detachment 731. It is also known as the Kamo Detachment (USSR 1950) and the Ishii Detachment or Ishii Unit (CIA 1947). Unit 731 was based in the Pingfang district of Harbin, the largest city in the Japanese puppet state of Manchukuo, but also had active branch offices throughout China and Southeast Asia. (Note that the Japanese word butai is variously translated with military terms such as "unit," "detachment," "regiment," or "company.")

Unit 731 was commanded until the end of World War II by General Ishii. The facility itself was built in 1935 as a replacement for the Zhongma Fortress, and Ishii and his team used it to expand their capabilities. The program received generous support from the Japanese government until the end of the war in 1945. Unit 731 and the other units of the Epidemic Prevention and Water Purification Department operated biological weapon production, testing, deployment and storage facilities. They routinely conducted tests on human beings (who were internally referred to as "logs"). Additionally, the biological weapons were tested in the field on cities and towns in China. Estimates of those who were killed by Unit 731 and its related programs range up to half a million people.

The researchers in Unit 731 were secretly given immunity by the United States in exchange for the data which they gathered during their human experimentation (Gold 1996). Other researchers that the Soviet forces managed to arrest first were tried at the Khabarovsk War Crime Trials in 1949. The Americans did not try the researchers so that the information and experience gained in bio-weapons could be co-opted into their biological warfare program, much as they had done with Nazi researchers in Operation Paperclip (Harris 2002). Victim accounts were then largely ignored or dismissed in the West as communist propaganda (Brody et al. 2014).

experiment unit 731

In 1932, Surgeon General Shirō Ishii ( 石井四郎 , Ishii Shirō ) , chief medical officer of the Imperial Japanese Army and protégé of Ministry of War of Japan Sadao Araki was placed in command of the Army Epidemic Prevention Research Laboratory (AEPRL). Ishii organized a secret research group, the "Tōgō Unit," for chemical and biological experimentation in Manchuria. Ishii had proposed the creation of a Japanese biological and chemical research unit in 1930, after a two-year study trip abroad, on the grounds that Western powers were developing their own programs.

One of Ishii's main supporters inside the army was Colonel Chikahiko Koizumi, who later became Japan's Health Minister (Minister of Health, Labor, and Welfare) from 1941 to 1945. Koizumi had joined a secret poison gas research committee in 1915, during World War I , when he and other Imperial Japanese Army officers were impressed by the successful German use of chlorine gas at the Second Battle of Ypres, in which the Allies suffered 5,000 deaths and 15,000 wounded as a result of the chemical attack (Williams and Wallace 1989).

Zhongma Fortress

Unit Tōgō was implemented in the Zhongma Fortress, a prison/experimentation camp in Beiyinhe, a village 100 km (62 mi) south of Harbin on the South Manchuria Railway. Prisoners were generally well fed on the usual diet of rice or wheat , meat , fish, and occasionally even alcohol, with the intent of having prisoners in their normal state of health at the beginning of experiments. Over several days, prisoners were eventually drained of blood and deprived of nutrients and water. Their deteriorating health was recorded. Some were also vivisected. Others were deliberately infected with plague bacteria and other microbes.

In the autumn of 1934, a prison break, which jeopardized the facility's secrecy along with a later explosion (believed to be sabotage) in 1935 led Ishii to shut down Zhongma Fortress. He then received authorization to move to Pingfang, approximately 24 km (15 mi) south of Harbin, to set up a new, much larger facility (Harris 2002).

In 1936, Emperor Hirohito authorized by decree the expansion of this unit and its integration into the Kwantung Army as the Epidemic Prevention Department (Barenblat 2005). It was divided at that time into the "Ishii Unit" and "Wakamatsu Unit," with a base in Hsinking (Changchun; it was renamed Hsinking during the Japanese occupation, serving as the capital of Imperial Japanese puppet state of Manchukuo). From August 1940, the units were known collectively as the "Epidemic Prevention and Water Purification Department of the Kwantung Army (関東軍防疫給水部本部)" (Tanaka 1996) or "Unit 731" (満州第731部隊) for short.

experiment unit 731

Other units

In addition to the establishment of Unit 731, the decree also called for the establishment of an additional biological warfare development unit called the Kwantung Army Military Horse Epidemic Prevention Workshop (later referred to as Manchuria Unit 100) and a chemical warfare development unit called the Kwantung Army Technical Testing Department (later referred to as Manchuria Unit 516). After the Japanese invasion of China in 1937, sister chemical and biological warfare units were founded in major Chinese cities and were referred to as Epidemic Prevention and Water Supply Units. Detachments included Unit 1855 in Beijing, Unit 1644 in Nanjing, Unit 8604 in Guangzhou, and later Unit 9420 in Singapore. All of these units comprised Ishii's network and at its height in 1939 was composed of more than 10,000 personnel (Keiichi 2005). Medical doctors and professors from Japan were attracted to join Unit 731 by the rare opportunity to conduct human experimentation and strong financial support from the Army (NHK 2017).

Human experiments

Human experimentation was conducted using men, women, and children — including infants, the elderly, and pregnant women — both inside the facility and among surrounding populations. The subjects included common criminals, captured bandits, anti-Japanese partisans, political prisoners, the homeless and mentally handicapped, and also people rounded up by the Kempeitai military police for alleged "suspicious activities." Ordinary citizens were also subjects to the tortures and death conducted by the researchers. The members of Unit 731 included approximately 300 researchers, including doctors and bacteriologists (Harris 2002). Many of the researchers had been desensitized to performing cruel experiments from experience in animal research (Cook and Cook 2000).

Test subjects were sometimes euphemistically referred to as "logs" ( 丸太 , maruta ) , used in such contexts as "How many logs fell?" This term may have originated by Unit 731 staff based on the fact that the official cover story for the facility was that it was a lumber mill. However, in an account by a man who worked as a junior uniformed civilian employee of the Imperial Japanese Army in Unit 731, the project was internally called "Holzklotz," which is a German word for log (Cook and Cook 2000). Researchers in Unit 731 published some of their results in peer-reviewed journals, writing as though the research had been conducted on non-human primates called "Manchurian monkeys," or "long-tailed monkeys" (Harris 2002).

Experiments conducted on subjects included those involving chemical agents and chemical weapons, biological agents and biological weapons, frostbite, vivisection, venereal diseases, and weapons testing, among others.

Chemical agents and chemical weapons

Unit 731 tested many different chemical agents on prisoners and had a building dedicated to gas experiments. Some of the agents tested were mustard gas, lewisite, cyanic acid gas, white phosphorus, adamsite, and phosgene gas (Gold and Totani 2019).

A former army major and technician gave the following testimony anonymously (at the time of the interview, this man was a professor emeritus at a national university) (Gold and Totani 2019):

In 1943, I attended a poison gas test held at the Unit 731 test facilities. A glass-walled chamber about three meters square and two meters high was used. Inside of it, a Chinese man was blindfolded, with his hands tied around a post behind him. The gas was adamsite (sneezing gas), and as the gas filled the chamber the man went into violent coughing convulsions and began to suffer excruciating pain. More than ten doctors and technicians were present. After I had watched for about ten minutes, I could not stand it any more, and left the area. I understand that other types of gases were also tested there.

Unit 731 also tested chemical weapons on prisoners in field conditions. A report authored by an unknown researcher in the Kamo Unit (Unit 731) describes a large human experiment of yperite gas (mustard gas) on September 7—10, 1940. Twenty subjects were divided into three groups and placed in combat emplacements, trenches, gazebos, and observatories. One group was clothed with Chinese underwear, no hat, and no mask, and was subjected to as much as 1,800 field gun rounds of yperite gas over 25 minutes. Another group was clothed in summer military uniform and shoes; three had masks, and another three had no mask. They also were exposed to as much as 1,800 rounds of yperite gas. A third group was clothed in summer military uniform, three with masks, and two without masks, and were exposed to as much as 4,800 rounds. Then their general symptoms and damage to skin, eye, respiratory organs, and digestive organs were observed at 4 hours, 24 hours, and 2, 3, and 5 days after the shots. Injecting the blister fluid from one subject into another subject and analyses of blood and soil were also performed. Five subjects were forced to drink a solution of yperite and lewisite gas in water, with or without decontamination. The report describes conditions of every subject precisely without mentioning what happened to them in the long run (Emanuel et al. 2011).

Biological agents and biological weapons

experiment unit 731

Unit 731 and its affiliated units were involved in testing of numerous biological agents on humans, including anthrax, typhoid , plague (infectious disease caused by the bacterium Yersinia pestis ), dysentery , tuberculosis , syphilis, tetanus, salmonella , tetrodotoxin (pufferfish or fugu venom), gas gangrene, meningitis, and yellow fever, including the deployment of epidemic-creating biowarfare weapons in assaults against the Chinese populace (both military and civilian) throughout World War II.

At least 12 large-scale field trials of biological weapons were performed, and at least 11 Chinese cities were attacked with biological agents. Plague-infected fleas , bred in the laboratories of Unit 731 and Unit 1644, were spread by low-flying airplanes upon Chinese cities, including coastal Ningbo and Changde, Hunan Province, in 1940 and 1941 (CIA 1947). This military aerial spraying killed tens of thousands of people with bubonic plague epidemics. An expedition to Nanking involved spreading typhoid and paratyphoid germs into the wells, marshes, and houses of the city, as well as infusing them into snacks to be distributed among the locals. Epidemics broke out shortly after, with the conclusion that paratyphoid fever was "the most effective" of the pathogens (Harris 2003; Barenblatt 2004). An attack on Changda in 1941 reportedly led to approximately 10,000 biological casualties and 1,700 deaths among ill-prepared Japanese troops, with most cases due to cholera (Christopher et al. 1997). In addition, poisoned food and candies were given to unsuspecting victims.

During the final months of World War II, Japan planned to use plague as a biological weapon against the United States in Operation Cherry Blossoms at Night. The plan was scheduled to launch on September 22, 1945, but Japan surrendered five weeks earlier (Baumslag 2005; Kristol 1995).

Due to pressure from numerous accounts of the bio-warfare attacks, Chiang Kai-shek sent a delegation of army and foreign medical personnel in November 1941 to document evidence and treat the afflicted. A report on the Japanese use of plague-infested fleas on Changde was made widely available the following year, but was not addressed by the Allied Powers until Franklin D. Roosevelt issued a public warning in 1943 condemning the attacks (Guillemin 2017).

Frostbite testing

Army Engineer Hisato Yoshimura conducted experiments by taking captives outside, dipping various appendages into water of varying temperatures, and allowing the limb to freeze (Tsuchiya 2007). Once frozen, Yoshimura would strike their affected limbs with a short stick, "emitting a sound resembling that which a board gives when it is struck" (Kristof 1995). The affected area was subjected to various treatments. For example, the best temperature for treating frostbite was found to be immersion in water slightly above 100 degrees but less than 122 degrees; this was found to be better than the traditional method of rubbing the affected limb (Kristof 1995).

experiment unit 731

Members of the Unit referred to Yoshimura as a “scientific devil” and a “cold blooded animal” (LaFleur et al. 2007). Naoji Uezono, a member of Unit 731, described in a 1980s interview a grisly scene where Yoshimura had “two naked men put in an area 40-50 degrees below zero and researchers filmed the whole process until [the subjects] died. The subjects suffered such agony they were digging their nails into each other’s flesh” (Emanuel et al. 2011). Yoshimura’s lack of remorse was evident in an article he wrote for the Journal Of Japanese Physiology in 1950 in which he admitted to using 20 children and a 3-day-old infant in experiments which exposed them to zero-degree-celsius ice and salt water (Yoshimura and Iida 1950). [Kristof (1995) reported about a three-day-old baby had a needle stuck into the middle finger to measure temperature; the needle prevented the hand from clenching into a fist and by keeping the finger straight it made the experiment easier.] Although this article drew criticism, Yoshimura denied any guilt when contacted by a reporter from the Japanese newpaper Mainichi Shinbun (Kei-ichi and Asano 1982).

Yoshimura developed a “resistance index of frostbite” based on the mean temperature 5 to 30 minutes after immersion in freezing water, the temperature of the first rise after immersion, and the time until the temperature first rises after immersion. In a number of separate experiments it was then determined how these parameters depend on the time of day a victim’s body part was immersed in freezing water, the surrounding temperature and humidity during immersion, how the victim had been treated before the immersion (“after keeping awake for a night,” “after hunger for 24 hours,” “after hunger for 48 hours,” “immediately after heavy meal,” “immediately after hot meal,” “immediately after muscular exercise,” “immediately after cold bath,” “immediately after hot bath”), what type of food the victim had been fed over the five days preceding the immersions with regard to dietary nutrient intake (“high protein of animal nature,” “high protein of vegetable nature,” “low protein intake,” and “standard diet”) and salt intake (45 g NaCl per day, 15 g NaCl per day, no salt) (Eckart 2006). This original data are seen in the above figure.


experiment unit 731

Thousands of men, women, children and infants interned at prisoner of war camps were subjected to vivisection (surgery on a living organism), often without anesthesia and usually ending with the death of the victim (Kristof 1995). Prisoners had limbs amputated in order to study blood loss. Those limbs that were removed were sometimes re-attached to the opposite sides of the body. Some prisoners had their stomachs surgically removed and the esophagus reattached to the intestines. Parts of organs, such as the brain, lungs, and liver, were removed from some prisoners (Parry 2007). Imperial Japanese Army surgeon Ken Yuasa suggests that the practice of vivisection on human subjects was widespread even outside Unit 731 (Kristof 1995), estimating that at least 1,000 Japanese personnel were involved in the practice in mainland China (Hongo 2007).

A former member of the Special Team (who insisted on anonymity) recalled in 1995 his first vivisection conducted at the Unit, involving a 30-year-old man tied to a bed naked, who was dissected without anesthetic (Kristol 1995):

He didn't struggle when they led him into the room and tied him down. But when I picked up the scalpel, that's when he began screaming. I cut him open from the chest to the stomach, and he screamed terribly, and his face was all twisted in agony. He made this unimaginable sound, he was screaming so horribly. But then finally he stopped.

Other sources suggest that it was the usual practice in the Unit for surgeons to stuff a rag (or medical gauze) into the mouth of prisoners before commencing vivisection, in order to stifle any screaming (Yang 2016).

Venereal diseases

To study the effects of untreated venereal diseases, male and female prisoners were deliberately infected with syphilis and gonorrhea , then studied. In some cases, this was done via injection, disguised as vaccinations (Medical Bag 2014).

Unit members also orchestrated forced sex acts between infected and non-infected prisoners to transmit the disease, as the testimony of a prison guard on the subject of devising a method for transmission of syphilis between patients shows (Gold and Tutani 2019):

Infection of venereal disease by injection was abandoned, and the researchers started forcing the prisoners into sexual acts with each other. Four or five unit members, dressed in white laboratory clothing completely covering the body with only eyes and mouth visible, rest covered, handled the tests. A male and female, one infected with syphilis, would be brought together in a cell and forced into sex with each other. It was made clear that anyone resisting would be shot.

After victims were infected, they were vivisected at different stages of infection, so that internal and external organs could be observed as the disease progressed.

Some children infected with syphilis grew up inside the walls of Unit 731. A Youth Corps member deployed to train at Unit 731 recalled viewing a batch of subjects that would undergo syphilis testing: "one was a Chinese woman holding an infant, one was a White Russian woman with a daughter of four or five years of age, and the last was a White Russian woman with a boy of about six or seven" (Gold and Tutani 2019). The children of these women were tested in ways similar to their parents, with specific emphasis on determining how longer infection periods affected the effectiveness of treatments.

Weapon testing

Unit 731 was involved in testing weapons on human subjects, including grenades, flamethrowers, explosives, and other weapons.

Human targets were used to test grenades positioned at various distances and in various positions. Flamethrowers were tested on people (Hickey et al. 2017). Victims were also tied to stakes and used as targets to test pathogen-releasing bombs, chemical weapons, shrapnel bombs with varying amounts of fragments, and explosive bombs as well as bayonets and knives.

To determine the best course of treatment for varying degrees of shrapnel wounds sustained on the field by Japanese soldiers, Chinese prisoners were exposed to direct bomb blasts. They were strapped, unprotected, to wooden planks that were staked into the ground at increasing distances around a bomb that was then detonated. It was surgery for most, autopsies for the rest. —Unit 731, Nightmare in Manchuria (Monchinski 2008; Neuman 2008)

Other experiments

In other tests, subjects were deprived of food and water to determine the length of time until death; placed into low-pressure chambers until their eyes popped from the sockets; experimented upon to determine the relationship between temperature, burns, and human survival; hung upside down until death; crushed with heavy objects; electrocuted; dehydrated with hot fans; placed into centrifuges and spun until death; injected with animal blood; exposed to lethal doses of x-rays ; subjected to various chemical weapons inside gas chambers; injected with sea water; and burned or buried alive (Kristof 1995; Silvester 2006).

Massive amounts of blood were drained from some prisoners in order to study the effects of blood loss according to former Unit 731 vivisectionist Okawa Fukumatsu. In one case, at least half a liter of blood was drawn at two to three-day intervals (Gold and Totani 2019). Unit 731 also performed transfusion experiments with different blood types. Unit member Naeo Ikeda wrote (Eckart 2006):

In my experience, when A type blood 100 cc was transfused to an O type subject, whose pulse was 87 per minute and temperature was 35.4 degrees C, 30 minutes later the temperature rose to 38.6 degrees with slight trepidation. Sixty minutes later the pulse was 106 per minute and the temperature was 39.4 degrees. Two hours later the temperature was 37.7 degrees, and three hours later the subject recovered. When AB type blood 120 cc was transfused to an O type subject, an hour later the subject described malaise and psychroesthesia in both legs. When AB type blood 100 cc was transfused to a B type subject, there seemed to be no side effect.

Female prisoners were forced to become pregnant for use in experiments, with the stated reason the possibility of vertical transmission (from mother to child) of diseases, particularly syphilis. Fetal survival and damage to mother's reproductive organs were objects of interest. Though "a large number of babies were born in captivity," there have been no accounts of any survivors of Unit 731, children included. It is suspected that the children of female prisoners were killed after birth or aborted (Gold and Totani 2019).

While male prisoners were often used in single studies, so that the results of the experimentation on them would not be clouded by other variables, women were sometimes used in sex experiments and as the victims of sex crimes. The testimony of a unit member that served as a guard graphically demonstrated this reality (Gold and Totani 2019):

One of the former researchers I located told me that one day he had a human experiment scheduled, but there was still time to kill. So he and another unit member took the keys to the cells and opened one that housed a Chinese woman. One of the unit members raped her; the other member took the keys and opened another cell. There was a Chinese woman in there who had been used in a frostbite experiment. She had several fingers missing and her bones were black, with gangrene set in. He was about to rape her anyway, then he saw that her sex organ was festering, with pus oozing to the surface. He gave up the idea, left and locked the door, then later went on to his experimental work.

Victims, including numbers of victims

experiment unit 731

The victims of Unit 731 included prisoners (criminals, anti-Japanese partisans, political dissidents, communist sympathizers, and those arrested for alleged suspicious activities), the homeless and mentally handicapped, and ordinary citizens. The victims included men, women, children, and infants. While the majority were Chinese, the victims also comprised Russians, Mongolians, Koreans, and other populations. There are reports that the victims also consisted of a small number of European, American, Indian, Australian and New Zealander prisoners of war (Wells 2009; Gold and Totani 2019; Harris 2002).

There have been widely varying estimates of the number of people killed due to activities of Unit 731. Sheldon Harris, an American historian, states that over 200,000 were killed in the germ warfare experiments (Harris 2002; Kristoff 1995). He also states that plague-infected animals released near the war's end killed at least 30,000 people in the Harbin area from 1946 through 1948 (Kristoff 1995). During a 2002 international symposium on crimes of bacteriological warfare held in Changde, China (site of a plague flea bombing), there was an estimate given of around 580,000 deaths caused by the germ warfare and human experiments (Barenblatt 2004). On the other hand, Keiichi Tsuneishi, a leading Japanese scholar of Unit 731, is skeptical of such high numbers (Kristoff 1995). At least 3,000 men, women, and children were subjected to experimentation conducted by Unit 731 at the camp based in Pingfang alone, which does not include victims from other medical experimentation sites, such as Unit 100 (Tsuchiya 2006). Note that in addition to Chinese casualties, 1,700 Japanese troops in Zhejiang during the Zhejiang-Jiangxi campaign were killed by their own biological weapons while attempting to unleash the biological agent (Rapoport 2014).

Known unit members

experiment unit 731

In April 2018, the National Archives of Japan disclosed a nearly complete list of 3,607 members of Unit 731 to Katsuo Nishiyama, a professor at Shiga University of Medical Science. Nishiyama reportedly intends to publish the list online to encourage further study into the unit (McCurry 2018).

Some of the previously disclosed members include:

  • Lieutenant General Shirō Ishii
  • Lieutenant Colonel Ryoichi Naito, founder of the pharmaceutical company Green Cross
  • Professor, Major General Masaji Kitano, commander, 1942–1945 (Christopher et al. 1997; Fuller 1992).
  • Kazuhisa Kanazawa, chief of the 1st Division of Branch 673 of Unit 731
  • Ryoichiro Hotta, member of the Hailar Branch of Unit 731 (Fuller 1992).

There were also twelve members who were formally tried and sentenced in the Khabarovsk War Crime Trials, held in December 1949 in the Soviet Union.

Unit 731 members sentenced in the Khabarovsk War Crime Trials
Name Military position Unit position (USSR 1950) Unit Sentenced years in labor camp (USSR 1950)
Kiyoshi Shimizu Lieutenant colonel Chief of General Division, 1939–1941, Head of Production Division, 1941–1945 (Fuller 1992) 731 25
Otozō Yamada General Direct controller, 1944–1945 (Fuller 1992) 731, 100 25
Ryuji Kajitsuka Lieutenant general of the Medical Service Chief of the Medical Administration (Fuller 1992) 731 25
Takaatsu Takahashi Lieutenant general of the Veterinary Service Chief of the Veterinary Service 731 25
Tomio Karasawa Major of the Medical Service Chief of a section 731 20
Toshihide Nishi Lieutenant colonel of the Medical Service Chief of a division 731 18
Masao Onoue Major of the Medical Service Chief of a branch 731 12
Zensaku Hirazakura Lieutenant Officer 100 10
Kazuo Mitomo Senior sergeant Member 731 15
Norimitsu Kikuchi Corporal Probationer medical orderly Branch 643 2
Yuji Kurushima [none] Laboratory orderly Branch 162 3
Shunji Sato Major general of the Medical Service Chief of the Medical Service (Fuller 1992) 731, 1644 20

Unit 731 was divided into eight divisions:

  • Division 1: research on bubonic plague , cholera , anthrax, typhoid and tuberculosis using live human subjects; for this purpose, a prison was constructed to contain around three to four hundred people
  • Division 2: research for biological weapons used in the field, in particular the production of devices to spread germs and parasites
  • Division 3: production of shells containing biological agents; stationed in Harbin
  • Division 4: bacteria mass-production and storage
  • Division 5: training of personnel
  • Divisions 6–8: equipment, medical and administrative units

experiment unit 731

Unit 731 had other units underneath it in the chain of command. Most or all units had branch offices, which were also often referred to as "Units." The term Unit 731 can refer to the Harbin complex itself or it can refer to the organization with its branches.

The Unit 731 complex covered 6 square kilometers (2.3 sq mi) and consisted of more than 150 buildings. The design of the facilities made them hard to destroy by bombing. The complex contained various factories. It had around 4,500 containers to be used to raise fleas , six cauldrons to produce various chemicals, and around 1,800 containers to produce biological agents. Approximately 30 kilograms (66 lb) of bubonic plague bacteria could be produced in a few days.

Unit 731 had branches in Linkou (Branch 162), Mudanjiang, Hailin (Branch 643), Sunwu (Branch 673), Toan and Hailar (Branch 543) (USSR 1950).

A medical school and research facility belonging to Unit 731 operated in the Shinjuku District of Tokyo during World War II. In 2006, Toyo Ishii — a nurse who worked at the school during the war — revealed that she had helped bury bodies and pieces of bodies on the school's grounds shortly after Japan's surrender in 1945. In response, in February 2011 the Ministry of Health began to excavate the site (AP 2011). While Tokyo courts acknowledged in 2002 that Unit 731 had been involved in biological warfare research, the Japanese government had made no official acknowledgment of the atrocities committed against test subjects, and rejected the Chinese government's requests for DNA samples to identify human remains (including skulls and bones) found near an army medical school (The Economist 2011).

Surrender and immunity

Operations and experiments continued until the end of the war. Ishii had wanted to use biological weapons in the Pacific War since May 1944, but his attempts were rejected.

Destruction of evidence and arrest

With the coming of the Red Army in August 1945, the unit had to abandon their work in haste. Ministries in Tokyo ordered the destruction of all incriminating materials, including those in Pingfang. Potential witnesses were killed — the 300 remaining prisoners were either gassed or fed poison and then were cremated; the 600 Chinese and Manchurian laborers were shot. Ishii swore every member of the group to silence and they were told to disappear (Altheide).

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Skeleton crews of Ishii's Japanese troops blew up the compound in the final days of the war to destroy evidence of their activities, but many were sturdy enough to remain somewhat intact.

Ishii and various leaders of Unit 731 was arrested by United States authorities during the Occupation of Japan at the end of World War II. They were supposed to be thoroughly interrogated by Soviet authorities (BBC 1984). Instead, Ishii and his team managed to negotiate and receive immunity from prosecution in 1946 from Japanese war-crimes prosecution before the Tokyo tribunal in exchange for their full disclosure (Brody et al. 2014; Kaye 2017).

The Soviet Union did arrest and prosecute twelve top military leaders and scientists from Unit 731 and affiliated units in the Khabarovsk War Crime Trials.

American grant of immunity

Among the individuals in Japan after its 1945 surrender was Lieutenant Colonel Murray Sanders, who arrived in Yokohama via the American ship Sturgess in September 1945. Sanders was a highly regarded microbiologist and a member of America's Military Center for Biological Weapons. Sanders' duty was to investigate Japanese biological warfare activity. At the time of his arrival in Japan he had no knowledge of what Unit 731 was. Until Sanders finally threatened the Japanese with bringing the Soviets into the picture, little information about biological warfare was being shared with the Americans. The Japanese wanted to avoid prosecution under the Soviet legal system, so the next morning after he made his threat, Sanders received a manuscript describing Japan's involvement in biological warfare. Sanders took this information to General Douglas MacArthur, who was the Supreme Commander of the Allied Powers responsible for rebuilding Japan during the Allied occupations. MacArthur struck a deal with Japanese informants: He secretly granted immunity from prosecution to the physicians of Unit 731, including their leader, Ishii, in exchange for providing America, but not the other wartime allies, with their research on biological warfare and data from human experimentation (Gold 2004).

Although the Soviet authorities wished the prosecutions to take place, the United States objected after the reports of the investigating US microbiologists. Among these was Edwin Hill, the Chief of Fort Detrick, whose report stated that the information was "absolutely invaluable;" it "could never have been obtained in the United States because of scruples attached to experiments on humans" and "the information was obtained fairly cheaply" (BBC 1984). On May 6, 1947, Douglas MacArthur wrote to Washington, D.C. , that "additional data, possibly some statements from Ishii probably can be obtained by informing Japanese involved that information will be retained in intelligence channels and will not be employed as 'War Crimes' evidence" (Gold 2004). The reason for the Americans granting immunity was that they believed that the research data was valuable and did not want other nations, particularly the Soviet Union, to acquire data on biological weapons (McNaught 2002).

The Tokyo War Crimes Tribunal heard only one reference to Japanese experiments with "poisonous serums" on Chinese civilians. This took place in August 1946 and was instigated by David Sutton, assistant to the Chinese prosecutor. The Japanese defense counsel argued that the claim was vague and uncorroborated, and it was dismissed by the tribunal president, Sir William Webb, for lack of evidence. The subject was not pursued further by Sutton, who was probably unaware of Unit 731's activities. His reference to it at the trial is believed to have been accidental.

Separate Soviet trials

Although publicly silent on the issue at the Tokyo Trials, the Soviet Union pursued the case and prosecuted twelve top military leaders and scientists from Unit 731, and its affiliated biological-war prisons Unit 1644 in Nanjing and Unit 100 in Changchun, in the Khabarovsk War Crime Trials. Included among those prosecuted for war crimes, including germ warfare, was General Otozō Yamada, the commander-in-chief of the million-man Kwantung Army occupying Manchuria.

The trial of those captured Japanese perpetrators was held in December 1949 in Khabarovsk, Russia, located in southeast Russia, near the border with China. A lengthy partial transcript of the trial proceedings was published in different languages the following year by a Moscow foreign languages press, including an English-language edition (USSR 1950). The lead prosecuting attorney at the Khabarovsk trial was Lev Smirnov, who had been one of the top Soviet prosecutors at the Nuremberg Trials . The Japanese doctors and army commanders who had perpetrated the Unit 731 experiments received sentences from the Khabarovsk court ranging from two to 25 years in a Siberian gulag (labor camp). The United States refused to acknowledge the trials, branding them communist propaganda (Tsuchiya 2011). The sentences doled out to the Japanese perpetrators were unusually lenient by Soviet standards, and all but one of the defendants returned to Japan by the 1950s (with the remaining prisoner committing suicide inside his cell). In addition to the accusations of propaganda, the US also asserted that the trials were only to serve as a distraction from the Soviet treatment of several hundred thousand Japanese prisoners of war; meanwhile, the USSR asserted that the US had given the Japanese diplomatic leniency in exchange for information regarding their human experimentation. The accusations of both the US and the USSR were true, and it is believed that the Japanese had also given information to the Soviets regarding their biological experimentation for judicial leniency (Vanderbrook 2013). This was evidenced by the Soviet Union building a biological weapons facility in Sverdlovsk using documentation captured from Unit 731 in Manchuria (Alibek and Handelman 2000).

There was consensus among US researchers in the postwar period that the human experimentation data gained was of little value to the development of American biological weapons and medicine.

Japanese history textbooks usually contain references to Unit 731, but do not go into detail about allegations (Selden and Nozaki 2009; Masalski 2001). Saburō Ienaga's New History of Japan included a detailed description, based on officers' testimony. The Ministry for Education attempted to remove this passage from his textbook before it was taught in public schools, on the basis that the testimony was insufficient. The Supreme Court of Japan ruled in 1997 that the testimony was indeed sufficient and that requiring it to be removed was an illegal violation of freedom of speech (Asahi Shimbun 1997).

In August 2002, the Tokyo district court ruled for the first time that Japan had engaged in biological warfare. Presiding judge Koji Iwata ruled that Unit 731, on the orders of the Imperial Japanese Army headquarters, used bacteriological weapons on Chinese civilians between 1940 and 1942, spreading diseases including plague and typhoid in the cities of Quzhou, Ningbo, and Changde. However, he rejected the victims' claims for compensation on the grounds that they had already been settled by international peace treaties (Watts 2002).

In October 2003, a member of the House of Representatives of Japan filed an inquiry. Prime Minister Junichiro Koizumi responded that the Japanese government did not then possess any records related to Unit 731, but the government recognized the gravity of the matter and would publicize any records that were located in the future. In April 2018, the National Archives of Japan released the names of 3,607 members of Unit 731, in response to a request by Professor Katsuo Nishiyama of the Shiga University of Medical Science (Japan Times 2018; McCurry 2018).

After WWII, the U.S. Office of Special Investigations created a watchlist of suspected Axis collaborators and persecutors who were banned from entering the United States. While they have added over 60,000 names to the watchlist, they have only been able to identify under 100 Japanese participants. In a 1998 correspondence letter between the DOJ and Rabbi Abraham Cooper, Eli Rosenbaum, director of OSI, stated that this was due to two factors. (1) While most documents captured by the US in Europe were microfilmed before being returned to their respective governments, the Department of Defense decided to not microfilm its vast collection of documents before returning them to the Japanese government. (2) The Japanese government has also failed to grant the OSI meaningful access to these and related records after the war, while European countries, on the other hand, have been largely cooperative (US Dept. of Justice 1998).

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Building on the site of Unit 731. Image courtesy of Wikimedia Commons.

By Avani Sihra

In the 1930s-‘40s, the Japanese Empire committed atrocities across Asia, such as the Rape of Nanking. German crimes such as human medical testing committed in concentration camps tend to receive more attention than Japan’s crimes against humanity, as more research has been done and more historians have spent time looking back and studying these horrific acts. However, the Japanese too played a part in human medical testing in a secret project called Unit 731.

Begun in 1937, Unit 731, located in Harbin, China, was created with legitimate intentions by the Japanese government. Started as an agency to promote public health, Unit 731 was meant to conduct research that would benefit Japanese soldiers, such as learning more about the ways in which the human body can withstand hunger and thirst and fight diseases. Early experiments were conducted on volunteers who had signed consent waivers, giving personnel permission. However, as the war intensified, they changed their methods.

Although the 1925 Geneva Accords had banned the use of biological or chemical weapons in warfare, the Japanese nevertheless wanted to prepare for these types of warfare. As these types of experiments were naturally ones that most people would not volunteer to take part in, the Japanese decided to use prisoners of war as their test subjects. Unit 731’s victims who were primarily Chinese and Russians, along with some Mongolians and Koreans.

The leader of the unit was Lieutenant General Shiro Ishii. Along with the other scientists he recruited, they experimented by infecting test subjects with different types of diseases to see how their bodies would respond to pathogens. As the Japanese destroyed most of the Unit’s records at the end of the war, little is known about the scientists who worked there.

Using the test subjects, the scientists injected different germs to see how they would react to one another in the human body, in an attempt to create new diseases. Referring to their victims as Maturas , or “wooden logs,” Japanese scientists would perform different types of procedures, such as vivisection, on live victims. Rats infected with the bubonic plague were released onto victims, with the intention of infecting the subjects so that they could be studied. Unit 731 was a place of torture that was, in the minds of many Unit 731 workers, a necessity in order to win the war .

Scientists in Unit 731 also experimented on their test subjects through pregnancy and rape. Male prisoners infected with syphilis would be told to rape female prisoners as well as male prisoners in order to see how syphilis spreads in the body. Women were involuntarily impregnated and then experiments were done on them to see how it affected the mother as well as the fetus. Sometimes the mother would be vivisected in order to see how the fetus was developing. 

Once it was clear that the Japanese were going to lose the war, unit workers destroyed much of the evidence of the experiments. Upon the formal surrender of the Japanese in August 1945, Unit 731 was officially terminated. The Japanese government did not admit to the wrongdoing committed by Unit 731 until very recently. The government did not acknowledge the atrocity until 1988, and even then, they did not apologize for what had happened. The project was highly secretive and much of the evidence had been destroyed; in addition, government officials who were aware of what happened in Unit 731 did not make their knowledge known to the public. Because of this lack of acknowledgment, the Chinese government took it upon themselves to spread awareness of the atrocities. In 1982, they established a museum in the same place where Unit 731 operated during the war.

Unlike some of the Nazi doctors who conducted experiments on prisoners and concentration camp inmates, none of those involved with the experiments at Unit 731 were ever punished for their crimes. Instead, after war’s end, many re-entered society and went on to have very successful careers in their fields. American forces , chiefly General Douglas MacArthur, decided not to put workers of Unit 731 on trial. MacArthur granted those involved immunity in exchange for the information they had gathered while doing their experiments. He believed that pursuing trials against these people would get in the way of the Americans receiving the medical information that had been documented from these experiments. Because of this decision, justice was never served.

Frank, Richard B. Downfall. Penguin Books, 1994.

Kristof, Nicholas D. “Unmasking Horror -- A special report; Japan Confronting Gruesome War Atrocity.” New York Times, https://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html . Accessed 3 May 2018.

Stockton, Richard. “Inside Unit 731, World War II Japan’s Sickening Human Experiments Program.” All That’s Interesting, http://allthatsinteresting.com/unit-731 . Accessed 3 May 2018.

Unit 731. Unit 731: Japan’s Biological Warfare Project, https://unit731.org/ . Accessed 3 May 2018.



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December 10

1936–1945: Unit 731 — the Asian Auschwitz

Japanese Medical Atrocities

1936–1945: Unit 731 — the Asian Auschwitz — was a massive biological warfare research program of the Japanese Imperial Army under the command of Lt. General Dr. Ishii Shiro in Pin Fang, Manchuria outside the city of Harbin. Its true purpose was masked as the Epidemic Prevention Research Laboratory. Unit 731 was housed within 150 buildings with a staff of 3,000. It included an aerodrome, railway line, barracks, dungeons, laboratories, operating rooms, crematoria, cinema, bar and Shinto temple. Its barbarous inhumane experiments rivalled the infamous Nazi death camp of Auschwitz-Birkenau, though the numbers of prisoners were smaller, it operated for a much longer period. From 1936 to 1942 between 3,000 and 12,000 men, women and children were subjected to unspeakable diabolical experiments, vivisected while still alive, before they were slaughtered in Unit 731. (C. Hudson, Doctors of Depravity , 2007; Nightmare in Manchuria, 2012; Unit 731 )

Shiro Ishii’s extensive deadly human experiments were under the protection of the Kanto Army High Command, the Kampeitei (secret Japanese police), and local police collaborators. His first laboratories were in the city of Harbin, later in Beiyinhe, and still later in an extraordinary facility in Harbin’s suburb known as Ping Fang.  Construction began in 1936, and was completed in 1939. Originally named Togo, later changed to Ishii Unit, finally it was named Unit 731; it was the world’s largest premier biological and chemical warfare research center.

“Each year hundreds of prisoners were fodder for fiendish experiments.  They were exposed to every known disease.  These ranged from anthrax to yellow fever.  Some were used for hyperthermia experiments.  Others were forced to endure gangrene experiments; and still others were forced to engage in sexual intercourse with individuals known to be infected with venereal diseases. They were then monitored as the disease took its toll on the victims.” “The victims were captured communist partisans, ordinary criminals, political dissidents, those who were mentally handicapped but physically fit, and, when candidates among these groups were scarce, the secret police would pick up the poor, the homeless, off the streets in cities throughout occupied China and Manchuria.  The police would be given orders to send prisoners to Harbin/Ping Fan by “Special Delivery.” “Everyone engaged in this sordid business understood that “Special Delivery” was the code words for new human experimental prey.  Prisoners to be tested were of various nationalities.  The overwhelming majority were Han Chinese.  However, Koreans, Soviet prisoners of varying ethnic backgrounds, and, occasionally, Europeans and Americans were used.” “Victims were frequently vivisected while still living.  They were not given an anesthesia since Ishii and his colleagues wanted to be certain that their tests were not influenced by an outside source.  Those individuals whose experiments required a course of study usually lasted about six weeks.  Then, of no longer any value to the researchers, they were “sacrificed”, the euphemism used instead of “killed.”  The bodies, men, women, and children, would then be dissected by pathologists, and, eventually, deposited in either large burial pits or burned in the three crematoria housed at Ping Fan.” (Sheldon Harris. Japanese Medical Atrocities in WWII: Unit 731 Was Not An Isolated Aberration .” A paper read at the International Citizens Forum on War Crimes & Redress, Tokyo, Dec. 11, 1999)

Unit 731 was divided into eight divisions: Division 1: Research on bubonic plague , cholera , anthrax , typhoid and tuberculosis using live human subjects in a prison was constructed to contain around 300 to 400 people. Division 2: Research for biological weapons used in the field, in particular the production of devices to spread germs and parasites. Shiro Ishii, the mastermind behind Japan’s biological warfare — “Factories of Death” — was a brash and flamboyantly corrupt man who considered himself a visionary” beyond scruples. He was brilliant, charming, intimidating, stone-hearted, driven to break new scientific ground and to help Japan defeat its foes. Ishii exhorted his team of physicians to violate the physicians’ ethical code:

“A doctor’s God-given mission is to challenge all varieties of disease-causing micro-organisms; to block all roads of intrusion into the human body; to annihilate all foreign matter resident in our bodies; and to devise the most expeditious treatment possible. . . However, the research we are now about to embark is the complete opposite of these principles, and may cause us some anguish as doctors.” “We pursue this research,” he explained, “for the double medical thrill; as a scientist . . . probing to discover the truth in natural science; and as a military person, to build a powerful military weapon against the enemy.” (Patrick Fong. Impunity Of Japan’s Secret Biological Warfare Unit , 2000.)

Unspeakably cruel and ghoulish experiments were conducted by Japanese physicians who had been recruited from Japan’s leading academic medical institutions. Like their Nazi counterparts, Japan’s physicians perverted the essence of medicine. Doctors in the biological war program turned life – biology – against life.

They referred to the prisoners as Maruta (“logs” whose killing was comparable to cutting down a tree). Army surgeons conducted many vivisections “for training purposes” — in truth, to desensitize them. The victims were mostly Chinese — men, women, and children, including pregnant women and infants. Soviet, Australian and several American prisoners of war were also subjected to experiments designed to infect the victims with fatal diseases including: plague, cholera, tuberculosis, typhoid, tetanus, anthrax, typhus, hemorrhagic fever, and dysentery. See, list “medically usable specimens” (i.e., pathogens) compiled in a U.S. occupation report . The victims were then vivisected — many while still alive. Live vivisection was a Japanese “specialty.”

The experiments conducted at Unit 731 and its satellites can be classified into the following broad categories: Vivisections for training new Army surgeons: These were performed at army hospitals in China using many Chinese prisoners. The doctors were trained to perform appendectomies and tracheotomies; prisoners were shot, then doctors removed the bullets from their bodies; they amputated their arms and legs and sewed up the skin around the wounds, and finally killed the prisoners. This surgical training program was to teach newly minted army surgeons how to treat wounded soldiers at the front lines. However, unlike normal medical training which teaches surgical skills while avoiding causing harm to patients, the training of these army doctors encourages causing needless harm and death. So, it has been suggested that training under Unit 731 supervision, was not required at all, but rather its main purpose was to desensitize the surgeons, rather than to perfect their surgical skills. (Takashi Tsuchiya.  Why Japanese doctors performed human experiments in China 1933-1945 ,  Eubios Journal of Asian and International Bioethics, 2000)

Intentional infecting with viruses and pathogens followed by vivisection either after death or vivisected to death. Doctors purposefully infected victims with diseases ;  victims would then be strapped down to an operating table and subjected to live autopsy without anesthesia. Some screamed in a non-human way when they realized their fate. Unit 731 “doctors” would cut them open to observe the progress of the germs incubating within them or to harvest organs that had enough germs to weaponize or spread on nearby villagers. They would amputate limbs to study blood loss and the effects of rotting and gangrene (some limbs were later attached to the other side of the body), parts of the stomach, liver, brains and lungs were often removed to observe the effects. The reason for live vivisection was to study the effect of the pathogens on live human organs and to avoid decomposition.

Germ warfare , male and female prisoners were injected with venereal diseases in the disguise of inoculations (or sometimes infected via rape) to determine the viability of germ warfare, victims were infested with fleas in order to communicate the disease to an organism which could be later dropped onto a populace. During one anthrax operation, the doctors noted the progress of the pathogen organ by organ. The victim’s suffering was unspeakable, with “his organs swelling, bleeding and disintegrating.” Fleas were also tainted with cholera, anthrax, and the bubonic plague, as well as, other plagues. This was the origin of the “flea bomb” which infected large geographic areas and polluted land and water. They were dropped in the guise of clothing and supplies which resulted in the estimated death of another 400,000–580,000 Chinese civilians. (Read more: China History Forum , 2005.)

Weapons testing,  grenades, mortars and other explosive devices were detonated near living targets to determine the effects with regards to different distances and angles, so they could determine how long victims could survive with their sustained injuries; experiments to determine the ability of the human body to survive in the face of various pathogens and in conditions such as extreme cold; Chinese prisoners were exposed to mustard gas in a simulated battle situation; others were tied to stakes tests to determine the lethality of biological, and chemical weapons and other explosive material.

Physical endurance experiments,  to determine the physical tolerance level of human beings. The experiments were designed to answer questions such as: how much air could be injected intravenously; how much poison gas could be inhaled; how much bleeding caused death; how many days prisoners could survive without food or water; how high electric current human beings could bear; air pressurized, oxygen deprivation experiments — same as those conducted in Nazi concentration camps; frostbite experiments where prisoners would lose entire limbs and suffer gangrene; forced sex between prisoners (most often one that was infected with a STD while the other was healthy). In other experiments victims were hung upside down to observe how long it took for one to die due to choking and the length of time until the onset of embolism occurred after inserting air into ones blood stream. Read more: Unit 731

Nonstardized treatment tests and Sadistic what if? Experiments . Numerous experimental vaccines were tested on prisoners with no animal trials; Victims were hung upside down to observe how long it took for one to die due to choking; the length of time until the onset of embolism occurred after inserting air into ones blood stream; what would happen if horse serum got injected into the body of a human?

“Other experiments were conducted so the doctors could learn more about how humans live and die. These included studies of dehydration, starvation, frostbite, air pressure – some inmates had their eyes blown out – transfusions of animal blood to humans and others. Even children and babies were destroyed this way. Other ghoulish experiments included cutting off a prisoner’s hands and sewing them back on to the opposite arms to gauge what happened.” ( China History Forum , 2005)

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Shiro ishii and the dark legacy of japan’s unit 731.

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Photo Credit: 1. Unknown Author / Bulletin of Unit 731 / Wikimedia Commons / Public Domain 2. Unknown Author / Wikimedia Commons / Public Domain (Colorized by Palette.fm)

Japanese physician Shiro Ishii presided over a series of abhorrent medical experiments that stand as some of the most egregious atrocities in modern history. Ranging from the development and testing of biological warfare agents to conducting live dissections on victims, the actions of Unit 731 constituted unspeakable crimes against humanity, targeting men, women and children in ways that defy comprehension, even by contemporary standards.

Shiro Ishii’s early life

Portrait of Shiro Ishii

Shiro Ishii’s background was one of prominence in feudal Japan, with his family being the largest landowners in their community. One of four siblings, his father earned a living as a local sake maker. Noted for his assertive demeanor, Ishii was characterized by his peers as “brash, abrasive, and arrogant” from a young age.

Following the completion of his medical studies at Kyoto Imperial University in 1920, Ishii embarked on a career in the Imperial Japanese Army (IJA) as a military surgeon. His exceptional performance garnered the admiration of his superiors, leading to an invitation to return to Kyoto Imperial University for post-graduate research in 1924.

Preferring bacterial cultures over human interaction

Portrait of Shiro Ishii

During this period, accounts from those who collaborated with Shiro Ishii paint a picture of his demeanor, characterized by what some described as “pushy behavior” and “indifference” toward his peers. Instead of forming connections with fellow his humans, Ishii’s affections were directed toward the bacterial cultures he cultivated in Petri dishes, which he treated as companions.

Known for his habit of lingering in laboratories well past regular hours, Ishii would use equipment painstakingly cleaned by students, intentionally leaving behind soiled instruments with the expectation that others would be punished. This odd and detached behavior foreshadowed Ishii’s later treatment of human subjects as mere objects.

Shiro Ishii wanted Japan to create a biological weapons program

Japanese soldiers marching toward an arch

By 1927, Shiro Ishii began promoting his aspirations to establish a Japanese biological weapons program, despite Japan having ratified the Geneva Protocol two years earlier, which prohibited the use of biological and chemical warfare. In early 1931, his dedication and loyalty to Emperor Hirohito, coupled with his frequent late-night endeavors in the laboratory, culminated in his promotion to Senior Army Surgeon, Third Class.

Around the time of Ishii’s promotion, China and Japan found themselves locked in a tense conflict. With the latter’s annexation of Chinese territories , an opportunity arose to establish testing facilities and capitalize on the ample number of Chinese prisoners to conduct abhorrent experiments on.

Ishii’s initial testing site was a facility known as Zhongma Fortress , in Beiyinhe, China. Approximately 1,000 prisoners were held within and subjected to harrowing tests, such as rigorous blood extraction sessions recurring every three to five days, relentlessly sapping their strength until they were rendered incapable to go on.

The facility ceased operations in 1936. However, by then, Ishii had set his sights on the establishment of a facility designed for even more depraved experiments.

Establishment of Unit 731

Aerial view of the Unit 731 main 'square building'

Promoted to the rank of Senior Army Surgeon, Second Class, Shiro Ishii assumed command of what became the infamous Unit 731 in 1936.

Operating under the guise of the Epidemic Prevention and Water Purification Department of the Kwantung Army, Unit 731 was a clandestine entity dedicated to chemical warfare research and development. However, the façade of its bureaucratic label belied its true nature. Unit 731 was a vehicle for the systematic torture and murder of countless innocents under the pretext of scientific advancement and national progress.

Under Ishii’s leadership, Unit 731 began a macabre initiative known as Maruta , wherein human beings were ruthlessly subjected to experimentation. The term originates from the Japanese word for “logs,” a grim reference to the callous manner in which test subjects were derisively labeled by their tormentors.

Officially cloaked as lumber mills, Unit 731 facilities operated under the guise of mundane industrial endeavors. To maintain the veil of secrecy surrounding their heinous activities, researchers and guards would casually refer to prisoners and victims as “logs,” employing coded language such as “How many logs fell today?” to obscure the true nature of their work.

Prisoners were subjected to horrific experimentation

Three Japanese scientists standing around a table with equipment placed atop it

Prisoners endured a litany of barbaric experiments under Unit 731.

They were systematically injected with virulent diseases, subjected to excruciating vivisections without anesthesia and compelled to endure a spectrum of torturous medical experiments. Procedures ranged from limb amputations aimed at studying blood loss to confinement in overheated chambers equipped with fans. Women were routinely subjected to assault, their bodies exploited to provide infants for further experimentation.

Many of these experiments were orchestrated to replicate battlefield conditions, serving as macabre simulations to enhance military medical knowledge and treatment protocols for combat-related injuries. Some prisoners were subjected to chilling conditions, forced to endure prolonged exposure to cold temperatures with their hands submerged in water. These aimed to provide insights into the treatment of frostbite injuries.

Meanwhile, others were subjected to the relentless forces of centrifuges, enduring intense pressure until the point where the sheer force caused their eyes to protrude from their sockets. These harrowing tests were conducted in an attempt to ascertain the limits of bodily endurance under extreme pressure.

Shiro Ishii had an obsession with the plague-bomb

Japanese plague-bombs lined up on the ground

A significant portion of Unit 731’s research was dedicated to Operation Cherry Blossoms at Night , an initiative orchestrated by Shiro Ishii that aimed at disseminating plague-infected rats across Allied-occupied territories during World War II . While the plan never came to fruition, the purported “research” phase of the project exacted a devastating toll on countless lives.

At least 12 large-scale field trials were conducted across 11 Chinese cities. One particular attack in 1941 resulted in the deaths of 10,000 locals and an additional 1,700 Japanese troops from cholera. Pathogens such as smallpox, anthrax, botulism and bubonic plague were weaponized and deployed in defoliation bacilli bombs or flea bombs, targeting densely populated areas.

Following the release of these plague-bombs, researchers, dressed in hazmat suits, monitored the effects on unsuspecting victims. By 1945, the Japanese had advanced preparations for the implementation of Operation Cherry Blossoms at Night, with plans to unleash thousands of plague-infested rats along California’s coast on September 22 of that year. However, the surrender of Japan occurred five weeks prior to the scheduled date.

Shiro Ishii was arrested for his war crimes

Portrait of Shiro Ishii

Shiro Ishii was arrested by the United States during the post-war Occupation of Japan . However, justice remained elusive. He and his associates negotiated a deal granting them immunity in return for divulging their insights into the Japanese military and their research endeavors.

Japanese medical authorities, when interviewed by American officials, adamantly portrayed themselves as mere microbiologists. An interviewer of Ishii’s associates attested to the “absolutely invaluable” nature of the information they supplied.

Following the 1948 immunity agreement, Ishii evaded prosecution for his war crimes and retreated from the public eye. Rumors regarding his whereabouts varied, with some suggesting he moved to Maryland, while others claimed he continued to reside in Japan, possibly practicing medicine.

More from us: USS Missouri (BB-63): American Battleship and the Site of the Japanese Surrender

Ishii passed away on October 9, 1959, succumbing to throat cancer in Shinjuku, Tokyo.

Japanese biological, chemical warfare unit (1936–1945) / From Wikipedia, the free encyclopedia

Dear wikiwand ai, let's keep it short by simply answering these key questions:.

Can you list the top facts and stats about Unit 731?

Summarize this article for a 10 year old

Unit 731 ( Japanese : 731部隊 , Hepburn : Nana-san-ichi Butai ) , [note 1] short for Manchu Detachment   731 and also known as the Kamo Detachment [3] :   198   and the Ishii Unit , [5] was a covert biological and chemical warfare research and development unit of the Imperial Japanese Army that engaged in lethal human experimentation and biological weapons manufacturing during the Second Sino-Japanese War (1937–1945) and World War II . Estimates vary as to how many were killed. Between 1936 to 1945, roughly 14,000 victims were murdered in Unit 731. [6] It is estimated that at least 300,000 individuals have died due to infectious illnesses caused by the activities of Unit 731 and its affiliated research facilities. [7] It was based in the Pingfang district of Harbin , the largest city in the Japanese puppet state of Manchukuo (now Northeast China ) and had active branch offices throughout China and Southeast Asia .

Unit 731
Location , , , (now )
DeathsEstimated 3,000 to 300,000 20

Established in 1936, Unit 731 was responsible for some of the most notorious war crimes which were committed by the Japanese armed forces . It routinely conducted tests on people who were dehumanized and internally referred to as "logs". Experiments included disease injections, controlled dehydration, biological weapons testing, hypobaric pressure chamber testing, vivisection , organ harvesting , amputation , and standard weapons testing. Victims included not only kidnapped men, women (including pregnant women) and children but also babies born from the systemic rape perpetrated by the staff inside the compound. The victims also came from different nationalities, with the majority being Chinese and a significant minority being Russian . Additionally, Unit 731 produced biological weapons that were used in areas of China not occupied by Japanese forces, which included Chinese cities and towns, water sources, and fields. Estimates of those killed by Unit 731 and its related programs range up to half a million people, and none of the inmates survived. In the final moments of the Second World War, all prisoners were killed to conceal evidence.

Originally set up by the military police of the Empire of Japan , Unit   731 was taken over and commanded until the end of the war by General Shirō Ishii , a combat medic officer. The facility itself was built in 1935 as a replacement for the Zhongma Fortress , a prison and experimentation camp. Ishii and his team used it to expand their capabilities. The program received generous support from the Japanese government until the end of the war in 1945.

Both the Soviet Union and United States gathered data from the Unit after the fall of Japan. While twelve Unit   731 researchers arrested by Soviet forces were tried at the December   1949 Khabarovsk war crimes trials , they were sentenced lightly to the Siberian labor camp from two to 25 years, in exchange for the information they held. [8] Those captured by the US military were secretly given immunity , [9] The United States helped cover up the human experimentations and handed stipends to the perpetrators. [1] The US had co-opted the researchers' bioweapons information and experience for use in their own warfare program (resembling Operation Paperclip ), so did the Soviet Union in building their bioweapons facility in Sverdlovsk using documentation captured from the Unit in Manchuria. [10] [8] [11]

On 28 August 2002, Tokyo District Court ruled that Japan had committed biological warfare in China and consequently was responsible for the deaths of many residents. [12] [13]

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A Scientific Method to the Madness of Unit 731’s Human Experimentation and Biological Warfare Program

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Kishor Johnson, A Scientific Method to the Madness of Unit 731’s Human Experimentation and Biological Warfare Program, Journal of the History of Medicine and Allied Sciences , Volume 77, Issue 1, January 2022, Pages 24–47, https://doi.org/10.1093/jhmas/jrab044

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The Japanese Imperial Army Unit 731’s Biological Warfare (BW) research program committed atrocious crimes against humanity in their pursuit of biological weapons development during the Second World War. Due to an American cover-up, the details behind Unit 731’s human experimentation were slow to be revealed. The recent literature discloses the gruesome details of the experiments but characterizes the human trials as crude in nature. Further, there is a lack of clarity as to how human trial results were extrapolated for use in real world missions.

Through an examination of testimony from the Soviet Union’s Khabarovsk War Crime Trials, this paper argues that Unit 731’s inoculation and airborne warfare experiments on prisoners of war were scientifically rigorous. The scientific method is used as the basis against which the scientific rigor of the experiments is tested. The paper reveals that the successes and failures of the human trials were extrapolated to BW missions during the Sino-Japanese war. American researchers’ expectations of BW data were fulfilled, thus paving the way for an immunity deal. Ethical standards in medicine before WWII were not well established, but wartime medical practices and experimentation reveal the context in which the pursuit of scientific knowledge has no boundaries.

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experiment unit 731

Dangerous World

Understanding Existential Risks

Unit 731: Imperial Japan’s Biological and Chemical Warfare

Written by Romeo Jung.


Unit 731 was a secret Biological and Chemical Warfare Unit that Imperial Japan had established during the World War II. Eager to win the war, the scientists involved committed a lot of inhumane crimes like vivisection to Chinese, Korean, Russian, and Mongolian prisoners of war, and used the data gained to harm many Chinese civilians. This essay details heavily on the biological research and its data from start to the end as well as their impacts and aftermath.

Unit 731 was established first in 1932 as a small group of five scientists interested in biological weapons, and was expanded around 1936 when Shiro Ishii was given full command of the unit. Given alternative names like “lumber yard” and “Epidemic Prevention and Water Purification Department of the Kwantung Army”, the name “Unit 731” was made formal in 1941.  The lab was based at the Epidemic Prevention Research Laboratory in Japanese Army Military Medical School in Tokyo. Their purpose was none of the given names, but biological and chemical warfare research.

The idea of Unit 731 first circulated around by a memo written in April 23, 1936, that speaks about the establishment of reinforcement military forces in Manchuria. The memo states that there would be a new “Kwantung Army Epidemic Prevention Department” and that it shall be expanded later on. 

The headquarters was set in three square kilometers of land in Pingfang district, Manchuria. Many of the lab’s buildings inside were hidden by a tall wall and high voltage wired fences. The lab had around 150 buildings, including incinerator, housing for prisoners, an animal house, and air field. The buildings were completely isolated from the outside world, with only a tunnel as the entrance.

Unit 731, along with two other units to be mentioned later, was created in opposition to the Geneva protocol of 1925 banning biological and chemical warfare. This protocol was signed at June 17, 1925 in Geneva. It became effective from February 8th, 1928, and got registered by League of Nations Treaty Series on September 7, 1929.

Within Unit 731, there were eight subunits designed to focus on different topics of warfare. The first division focused on biological weapons like bubonic plague, cholera, anthrax, typhoid, and tuberculosis, with human subjects to work with. The second division  focused on effectively spreading the biological weapons covered in the first division. The third division was focused on a specific way of spreading biological agents by bomb, the fourth on bacteria mass production and storage. The fifth through eighth divisions  were mostly focused on the supplying the rest of the Unit, which included training workers, providing equipment, and overall administrative units.

Outside of Unit 731, Japan established two departments: Unit 100 and Unit 516. Unit 100 was first declared as the “Kwantung Army Military Horse Epidemic Prevention Workshop,” which focused on developing biological weapons aside from Unit 731. “Kwantung Army Technical Testing Department”, later called Unit 516, was also established for more research that focused on chemical weapons. 

People Involved

There were many involved with the research of Unit 731, most of them remaining anonymous to this day. Shiro Ishii was the Chief of Unit 731, with Masaji Kitano as second in command. Other scientists were most likely to be a Professor at an university or a chief of a medical research unit, like Dr. Hisato Yoshimura, who directed the frostbite experiments on subjects, and Dr. Hideo Futaki, who lead the tuberculosis research squad and some vivisections. Other personnels include Lieutenant Shunichi Suzuki, who, after the trials, went to work as the Governor of Tokyo, and Amitani Shogo, who remained at the lab afterwards and received the Asahi Prize for outstanding scientific performance.

Shiro Ishii served in the Imperial Japanese Army from 1921 to 1945, and in the meantime, he was a Japanese army medical officer, microbiologist, and the director of Unit 731. Before serving in the army, he had studied medicine at Kyoto Imperial University. He was first assigned as an army surgeon, then to the First Army Hospital and Army Medical School in Tokyo. His work soon impressed the superiors, which earned him postgraduate level medical education. Ishii was promoted to an army surgeon in 1925, and was advocating for a biological weapons research program.

After getting promoted to higher ranks, Ishii began his experiments in Zhongma Fortress for biological weapons. Then the government granted him permission to set up Unit 731 in his hopes of digging deeper into the topic. After World War II, he was arrested for a short time by the US occupation authorities for Unit 731, then received immunity from consequences in exchange for data. There are different accounts as to what he did after that, but some say that he traveled around to give talks about biological weapons and others say that he stayed in Japan to provide medical services for free.

What They Did

In Unit 731, the first division conducted many outrageous experiments which were violating human rights. They conducted   many experiments that tested the limitations of the human body. The prisoners, used as subjects, were of mixed ethnicity and gender, some pregnant, and some as young as three years old.  The prisoners, tied to stakes, would have to endure the biological agent bombs that carried plague infested fleas on them or rats with the diseases. Then they were subject to their body being cut open with a scalpel and examined while they were screaming for mercy on the table. 

An unnamed Unit 731 surgeon, in an interview with  New York Times, described his experience with the unit. His first vivisection, which he recalled that he “cut [the prisoner] open from the chest to the stomach, and he screamed terribly, and his face was all twisted in agony… …finally he stopped. This was all in a day’s work for the surgeons…” (Kristof) There was no use of anesthetics during vivisections at all because they were afraid that it would have an effect on the results and data.

In another part of his article, Kristof interviews a former medical worker in Unit 731, Takeo Wano. Wano says that he had seen “six-foot-high glass jar in which a Western man was pickled in formaldehyde. The man had been cut into two pieces, vertically.” There were many other jars in the headquarters of Unit 731 containing other body parts from different people, labeled often as their ethnicity. An anonymous Unit 731 veteran says that most of the jars had been noted as Chinese, Korean, and Mongolian, although there were occasionally American, English, and French. Some body parts were even sent in from other places.

Other experiments included prisoners being locked inside a pressure chamber to test how much pressure the body can handle before their eyes started popping out, being exposed to poisonous gas and many more biological and chemical weapons, having limbs cut off for studying blood loss, having cut off limbs attached to different parts of the body, having horse urine injected into kidneys, and having lethal dosages of x-rays. Kristof noted that “The accounts are wrenching to read even after so much time has passed: a Russian mother and daughter left in a gas chamber, for example, as doctors peered through thick glass and timed their convulsions, watching as the woman sprawled over her child in a futile effort to save her from the gas.”

Hisato Yoshimura, apart from infection based experiments, led the frostbite experiments, which focused on the effects of frostbite on human limbs. He gave orders to freeze limbs of prisoners, often until they were black. The prisoners were let in only when an officer was sure that their limbs were frozen. The officers would test limbs by beating them with a stick, as they knew that frozen limbs sound like wooden boards upon hitting. 

After chilling prisoners’ limbs to near 0 degrees Celsius with ice water, Yoshimura continued to chop off parts of the limb, especially fingers, so that he may record how the frostbite was affecting human limbs. He and his team experimented on subjects as young as three years old, with a needle in their finger to keep it from clenching into a fist. 

Effects During War

The Japanese Military used the biological weapons developed by Unit 731 directly on Chinese civilian population. Agents in divisions other than the first division in Unit 731 would spread the diseases by train, road, and airplanes. Many Chinese civilians developed the worst infections on their limbs, and only a few were exposed to treatment since no local doctors or hospitals had seen the infections before.

Quzhou village, Ya Fan village, and Chong Shan village in the Zhejiang Province had suffered deeply from the Bubonic Plague, as well as Dysentery, Typhoid, Cholera, and many more. In an episode of BBC Correspondent,  Wu Shi-Gen, a victim of Unit 731’s biological weapons, tells his story of how the Bubonic Plague had affected his nine-year old brother. The rest of the family chose to lock his little brother away in another room to minimize the possibilities of infections while the little boy cried out from the room. Wu said he still remembers how he could not run in and help his brother when he cried out in pain.

Ya Fan village was affected with an unknown infection, commonly known to residents as “The Rotten Leg Disease.” A victim of this infection describes it as something that “started like an insect bite, then swelling and unbearable pain. Then his flesh started rotting away. Many died of it. Experts say it’s probably Glanders, another of Unit 731’s special recipes. Treatments were ineffectual and cost a fortune.” He stated that while his mother and he both had the disease on their legs, she refused the medicine so that he could have it instead of her. She passed away a few months later.

Aside from negative effects, Unit 731’s research was also used to heal Japanese soldiers with certain conditions. Studying about human conditions like frostbites and different diseases, the doctors could effectively pinpoint medical solutions for their sick soldiers. For instance, the frostbite experiment revealed that putting frozen limbs in water from 100 to 122 degrees Celsius is the best.

As soon as the World War II was over, the scientists at Unit 731’s headquarters started burning the building down, getting rid of all the evidence. When Shiro Ishii and many others were captured by China and sent over to the US for a trial, they had a deal with President MacArthur. He decided to let go of the Unit 731’s scientists free of charge for the war crimes in exchange for their medical research data.

In addition, Japanese government was fairly late to apologize to the rightful victims of Unit 731, while paying war tributes to the dead war criminals of Unit 731. They have been continuously visiting their shrines every year since 2013, offending neighboring countries and victims. Many news articles had been written about it, yet they do not seem to matter to the Japanese government.

Many Japanese scholars also deny the fact that there was ever a Unit 731 and state that the history involving the group is fabricated, although there are plenty of evidences. The Japanese history textbooks do not cover most of Japan’s horrific acts in World War II, leading them to believe that Japan was mostly a victim country rather than hostile like their opponents. By large, the Japanese public has a false sense of history due to the fact that their history textbooks are skewed. 

The former members of Unit 731 seem to have conflicting opinions about the publicity of the topic. Yoshio Shinozuka and some others had gone to give talks and share information about Unit 731, but others like Toshimi Mizobuchi intend to keep the promise to hide the information. A portion of Unit 731 members still hold their annual staff reunion parties hosted by Mizobuchi.

Unit 731 has been one of of the most cruel groups to do human experimentation, yet so few people that I’ve met know about what really happened. Although these inhumane experiments could be defended by saying that they were useful for modern medical science, they were definitely not worth the cost of many civilian lives as well as prisoners’ suffering.

Maruta — “Log” in Japanese. Prisoners were often called logs so that they could be experimented on without scientists feeling remorse.

Vivisection —  Much like dissection, but with an alive person.

Unit 731: Japan’s Biological Warfare Project. (2018). Retrieved March 14, 2018, from https://unit731.org/ Kristof, N. D. (1995, March 17). Unmasking Horror — A special report.; Japan Confronting Gruesome War Atrocity. Retrieved March 24, 2018, from https://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html?pagewanted=all L. (2013, February 11). Unit 731: Japan’s biological force. Retrieved March 24, 2018, from https://www.youtube.com/watch?v=8LfMNX3TsT0 Working, R. (2001, June 5). The trial of Unit 731. Retrieved March 24, 2018, from https://www.japantimes.co.jp/opinion/2001/06/05/commentary/world-commentary/the-trial-of-unit-731/#.WqoQ6z9zJhE McCurry, J. (2013, December 26). Japan’s Shinzo Abe angers neighbours and US by visiting war dead shrine. Retrieved March 24, 2018, from https://www.theguardian.com/world/2013/dec/26/japan-shinzo-abe-tension-neighbours-shrine Beijing, S. A. (2014, October 17). China protests at Japanese PM’s latest WW2 shrine tribute. Retrieved March 24, 2018, from https://www.theguardian.com/world/2014/oct/17/china-protests-japan-shinzo-abe-yasukuni-shrine Japanese PM Abe sends ritual offering to Yasukuni shrine for war dead. (2017, October 17). Retrieved March 24, 2018, from https://www.reuters.com/article/us-japan-yasukuni/japanese-pm-abe-sends-ritual-offering-to-yasukuni-shrine-for-war-dead-idUSKBN1CL355 Abe training jet photo sparks outrage in South Korean media. (2013, May 15). Retrieved March 24, 2018, from http://www.scmp.com/news/asia/article/1238533/abe-training-jet-photo-sparks-outrage-south-korean-media Tsuneishi, K. (2005, November 24). Unit 731 and the Japanese Imperial Army’s Biological Warfare Program. Retrieved March 24, 2018, from https://apjjf.org/-Tsuneishi-Keiichi/2194/article.html Pure Evil: Wartime Japanese Doctor Had No Regard for Human Suffering. (2016, June 15). Retrieved March 24, 2018, from https://www.medicalbag.com/despicable-doctors/pure-evil-wartime-japanese-doctor-had-no-regard-for-human-suffering/article/472462/ Tsuchiya, T. (2007, December 16). Retrieved March 24, 2018, from http://www.lit.osaka-cu.ac.jp/user/tsuchiya/gyoseki/presentation/UNESCOkumamoto07.html Unit 731: One of the Most Terrifying Secrets of the 20th Century. (n.d.). Retrieved March 26, 2018, from https://www.mtholyoke.edu/~kann20c/classweb/dw2/page1.html

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United States Responses to Japanese Wartime Inhuman Experimentation after World War II: National Security and Wartime Exigency

Howard brody.

Director, Institute for the Medical Humanities, University of Texas Medical Branch, Galveston, TX USA

Sarah E. Leonard

Institute for the Medical Humanities, University of Texas Medical Branch, Galveston, TX USA

Jing-Bao Nie

Bioethics Centre, Division of Health Science, University of Otago, New Zealand; (adjunct/visiting) Hunan Normal University and Peking University, China

Paul Weindling

Department of History, Philosophy and Religion, Oxford Brookes University, Oxford, UK

In 1945-46, representatives of the United States government made similar discoveries in both Germany and Japan, unearthing evidence of unethical experiments on human beings that could be viewed as war crimes. The outcomes in the two defeated nations, however, were strikingly different. In Germany, the U.S., influenced by the Canadian physician John Thompson, played a key role in bringing Nazi physicians to trial and publicizing their misdeeds. In Japan, the U.S. played an equally key role in concealing information about the biological warfare experiments and securing immunity from prosecution for the perpetrators. The greater force of appeals to national security and wartime exigency help to explain these different outcomes.

In 1945-46, U.S. officials made similar discoveries in both Germany and Japan, unearthing evidence of unethical experiments on human beings that constituted war crimes. The outcomes in the two defeated nations, however, were strikingly different. In Germany, the U.S. played a key role in bringing Nazi physicians to trial and publicizing their misdeeds. In Japan, the U.S. played an equally key role in concealing biological warfare experiments and securing immunity for the perpetrators. How we are to understand these very different responses?

Sheldon Harris, in his authoritative history of the Japanese biological warfare program, argues that during November 1945-March 1948:

The questions of ethics and morality as they affected scientists in Japan and in the United States never once entered into a single discussion… In all the considerable documentation that has survived…, not one individual is chronicled as having said [biological warfare] human experiments were an abomination and that their perpetrators should be prosecuted. The only concern voiced was that of the possibility of exposure that would cause the United States some embarrassment should word of the bargain ever become public knowledge. 1 , p. 305

In alleging that “questions of ethics and morality” were never raised, Harris seems to mean that no questions were answered in ways he agreed with. Much as we sympathize with his moral outrage, his statement is uninformative about the actual reasoning that the U.S. scientists employed as justification.

It is informative to compare the American response in Japan with the work of one important figure in Germany, Canadian Air Force officer John W. Thompson. Thompson recognized the German experiments as war crimes that set a dangerous precedent for the scientific community, and was uniquely influential in persuading Allied authorities to act. 2

We first briefly summarize the experiments in the two countries, then describe Thompson’s activities in postwar Germany. We next recount the U.S. investigations of Japanese biological warfare experiments. We conclude by comparing the two Allied responses to medical war crimes and propose reasons for the difference.

German and Japanese Experiments

The scope and nature of these unethical experiments is well described elsewhere. 1 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 A database created by Paul Weindling’s group at Oxford Brookes University has identified approximately 25,000 victims of German experiments, with confirming documentation for around 10,000. 3 Only about five percent of experiments ended with the death of the subjects but many others caused severe mutilation. 3

While Japanese biological warfare experiments were conducted at several locations, the best known is Unit 731, located near Harbin in Japanese-occupied Manchuria and commanded by Shiro Ishii. Established in 1936, Unit 731 eventually comprised 3000 personnel, 150 buildings, and capacity for holding 600 prisoners at a time for experimental use. Thousands of human beings were experimented on and killed at Unit 731 alone. Additional thousands were killed in other branches of Japan’s extensive biological and chemical warfare program. It is unlikely that accurate totals will ever become available. 1 , pp. 86-87

The Unit 731 experiments involved infecting prisoners, primarily Chinese prisoners of war and civilians, deliberately with infectious agents, and exposing prisoners to bombs designed to penetrate the skin with infectious particles. There were no known survivors of these experiments; those who did not die from infection were killed to be studied at autopsy, and in the waning days of the war all remaining prisoners were killed to conceal evidence. Some experiments were also done to test human responses to freezing temperatures and other extreme conditions.

Japanese military units also carried out field testing of disease-spreading weapons against both enemy troops and civilian populations. Additional thousands of deaths were caused by spreading plague-infected fleas and cholera bacilli in China in this manner, even though the experimenters developed no really efficient and well-controlled method for dispersing such agents.

The Nazis justified their experiments on three grounds—racist, eugenics/public health, and wartime national interests. The victims (primarily Jews, Roma, and Soviet prisoners of war) were believed to be racially inferior to the German-Aryan stock. Nazi party propaganda, especially effective among physicians, described the threat posed to the German people ( volk ) by racial contamination and unbridled reproduction among those with “unfit” genes. With the start of war in 1939, the attitude had been created that it seemed indefensible that the flower of German youth were facing death on the battlefield unless these racially inferior beings were also sacrificed for the war effort. 4

Two of these justifications motivated the Japanese. They viewed the Chinese and Koreans as racially inferior. 10 They also appealed frequently to patriotism. 11 They were not, however, concerned about threats to Japanese racial purity; rather they simply wished to eliminate inferior populations and occupy their territories for Japanese imperialist expansion. The Japanese also argued that the prisoners used as experimental subjects, as suspected resisters and communists, would have been executed in any event.

The Role of John W. Thompson

A person whose important role in post-war events has not been sufficiently recognized is John W. Thompson. Born in Mexico of American parents, educated in the U.S., and a medical graduate of Edinburgh, John West Thompson (1906-1965) entered World War II as an officer in the Royal Canadian Air Force (RCAF). 2 Thompson possessed varied expertise. He was a skilled enough psychiatrist to assess German war crimes defendants for underlying psychopathology. He was prominent enough in medical research later to be offered (and decline) the physiology chair at the University of Ottawa in 1946. He had studied high-altitude flying, fitting him to evaluate German wartime research in that area. Finally, he had worked at Harvard during the 1930s with physiologists Andrew Ivy and Leo Alexander, who became central figures in the Nuremberg Doctors’ Trial. 12 , 13

When he arrived in Germany in May, 1945, Thompson’s first experience involved the care of the survivors of the Bergen-Belsen concentration camp. Even after liberation, deaths mounted alarmingly from malnutrition, a typhus epidemic, and inadequate medical response.

Thompson was then assigned the task of assessing the results of German aeronautical-stress research. He quickly discerned that much of this research was conducted in an unethical manner, as was confirmed by interviews with both German scientists and surviving subjects. Eventually Thompson was named Secretary-General of the International Scientific Commission (War Crimes). However, Thompson’s influence was exercised largely through personal contacts and diplomacy. Weindling believes that his behind-the-scenes role was important enough to merit the title “godfather of both the Nuremberg Code and informed consent.” 2 , p. 148

In November 1946, Thompson outlined his plans for the International Scientific Commission in a report to Lester Pearson, then Canada’s Under Secretary of State for External Affairs:

…[T]o gather all evidence of German experimental work carried out in an unethical manner on human beings, and as representative scientific bodies, to pass judgment on the value of the scientific results obtained condemn, in the name of science, the prosecution of such experiments, and finally, lay down some definition of what may be termed a justifiable experiment where a human being is used as a subject. 2 , p.125

These priorities reflect several ethical judgments. First, while the medical superintendent of the United Nations Relief and Rehabilitation Administration, T.B. Layton, had argued that all Nazi medical research data should be destroyed, 2 , p. 93 , Thompson thought that science demanded that any valuable results be preserved. At the same time he viewed the means of obtaining those data as unethical and criminal. Indeed, Thompson appears responsible for introducing the idea of a “medical war crime” into the official thinking of the Allied occupation in November 1945. Finally, when many thought the Nazis uniquely depraved, Thompson worried that scientists in other nations were equally capable of conducting unethical human experiments unless clear ethical boundaries were erected.

Thompson’s scientific intelligence team preserved and microfilmed a treasure trove of captured German research records—files later used by the Nuremberg prosecutors at the Doctors’ Trial. They also interviewed many Nazi scientists, but never discussed trading immunity from prosecution for access to scientific information. Among the many examples of the influence Thompson exerted over the U.S.-led responses through his personal diplomacy was helping to assure that the scientific intelligence work was closely coordinated with war crimes investigation units.

Japan: Scientific Investigations

The Japanese scientists were more astute than the Germans, both in banding together to plan their response to the American investigations and in realizing that the American interest in their data gave them a powerful bargaining chip. Like Scheherazade in the Arabian Nights tales, the Japanese interrogees became adept at revealing just enough in each interview, leaving what was yet unsaid as a tantalizing demonstration of how valuable their continued freedom would be to U.S. interests. 1 , p. 265

Lt. Col. Murray Sanders, a bacteriologist was the first investigator from the U.S. biological warfare unit at Camp Detrick, Maryland to travel to Japan. Sanders was told by several interviewees in September and October 1945 that the Japanese military had engaged solely in defensive research, as biological warfare was “clearly against humanity.” 14 The repetition of this phrase suggested a prearranged script. Sanders trusted his translator, Lt. Col. Ryoichi Naito, not realizing that Naito had served in Unit 731 and was deliberately manipulating the interrogations. In a 1983 interview, Sanders admitted that he had been “deceived” during his nine-week investigation 1 , p.182

The second American investigator, Lt. Col. Arvo T. Thompson, was similarly unable to extract correct information, but left in May 1946 increasingly convinced that the truth was being withheld. Gen. Ishii told Thompson that biological warfare was “inhumane” and would (if the Japanese had conducted such research) “defile the virtue and benevolence of the Emperor.” 15 This was a clear statement from a Japanese source, however cynically provided, that biological warfare experiments were unethical.

The third American scientist-investigator, Dr. Norbert H. Fell, a civilian employee of Camp Detrick, arrived in 1947. Fell was more knowledgeable than his two predecessors, whose reports had primed him to look out for deception. After testing Fell, Ishii’s group apparently decided to reveal that human experiments had, in fact, been conducted for biological weapons development. Their selected go-between was a “prominent businessman,” Kanichiro Kamei, whom Fell interviewed on April 21-22, 1947. Kamei was a PhD from Columbia University who had earlier served as a translator during the investigation conducted by Murray Sanders, said that despite his efforts to “persuade the Japanese to reveal everything,” 16 “the interrogations…were too soon after the surrender. However, if the men who actually know the detailed results of the experiments can be convinced that your investigation is from a purely scientific standpoint, I believe that you can get more information. … I believe it will reassure any personnel…that you are not investigating ‘war crimes.’” Referring to a Japanese officer being interrogated, Kamei told Fell, “MASUDA admitted to me that experiments were carried out on humans…. The personnel involved in carrying out these human experiments took a vow never to disclose information. However, I feel sure that if you handle the investigation from a scientific point of view, you can obtain detailed information.” 17

Two days later, Kamei stated that the Japanese feared that information given to the US “will be discovered by Communists and passed to Russia.” Those behind Kamei now saw that an emerging U.S. priority was keeping biological warfare information out of Communist hands. Kamei told Fell, “The human experiments were extensive enough to reach scientific conclusions. …conclusions [that] are in no way based on imagination.” 18 Having previously lied that all documents had been destroyed and that the surviving officers of Unit 731 had only hazy recollections of experiments, the Japanese now changed course and reassured the Americans that they had valuable information to trade for immunity from prosecution.

Fell, therefore, became the first American scientist made directly aware of activities that clearly constituted war crimes (assuming that the human experiments had been carried out without any semblance of voluntary consent). His response was to adopt Kamei’s proposal, that almost certainly originated with Ishii. Fell proceeded to inform each interrogated subject, “Investigation was to obtain scientific and technical data and was not concerned with ‘war crimes.’” 1 , p. 275, 19 Harris is unsure who authorized Fell to offer such assurances; Fell lacked the military authority to make such a move on his own. 1 , p. 278

However, in an addendum to his final report, dated June 24, 1947, Fell noted that the “information that has been received so far is proving of great interest here and it certainly will have a great deal of value.” 20 He then added:

At a conference yesterday at which the Chief of the Chemical Corps and representatives of the War, State and Justice Departments were present, it was informally agreed that the recommendations of the C.inC., FEC [Commander-in-Chief, Far East Command, i.e. General Douglas MacArthur], and the Chief, Chemical Corps would be accepted, i.e. that all information obtained in this investigation would be held in intelligence channels and not used for ‘War Crimes’ programs. 17

Harris argues that the Joint Chiefs of Staff would have had to approve a decision of this gravity, 1 , p. 278 and they in turn would have proceeded only with cabinet-level if not Presidential approval. 1 , p. 279 This decision kept all information about the human biological warfare experiments within intelligence channels, labeled top secret, whereas war crimes prosecution would entail public disclosure. The Fell report shows that these options were weighed and that scientific and military value took priority over ethical and criminal accountability.

The final report by U.S. scientists from Camp Detrick was submitted in December 1947, by technical director Dr. Edwin V. Hill and staff pathologist Dr. Joseph Victor. Ishii’s group now gave the Americans detailed reports on the experimental program, including a listing of 8000 pathological slides and hundreds of color drawings.

From an ethical standpoint, the Hill-Victor report is most notable for statements that have since been widely quoted. 21 Hill and Victor summarized the Japanese data, “Such information could not be obtained in our own laboratories because of scruples attached to human experimentation….It is hoped that the individuals who voluntarily contributed this information will be spared embarrassment because of it and that every effort will be taken to prevent this information from falling into other hands.” 22 The ethical reasoning implicit in this passage seemed to be:

  • U.S. scientists have “scruples” regarding experimentation on humans. The Japanese scientists had no such scruples, indicating that their activities were unethical if not criminal.
  • Having conducted unethical and criminal experiments, the Japanese scientists are therefore in a position to be embarrassed by their revelation.
  • Saving the Japanese scientists (who belatedly cooperated with the U.S. inquiry) from embarrassment is a higher ethical priority than securing accountability for war crimes.
  • The overriding goals are first, to secure these unique (because unscrupulous) data for the U.S., and second, to prevent them from “falling into other [i.e., Communist] hands.”

Hill and Victor added a further argument based on cost-effectiveness. They calculated that the U.S. had so far spent approximately 250,000 yen in its investigations of the Japanese biological warfare program. By contrast, Ishii’s research had cost “many millions of dollars and years of work” (with no mention of the human costs in lives and misery). In short, the U.S. had paid proportionally a “mere pittance” compared to the cost of generating these data. 19 This became a further argument for taking the data and assuring that the Japanese who provided it were not subjected to “embarrassment.”

Although conjecture, it is tempting to read into these statements a further conclusion that the Americans, contrasting their slow progress at Camp Detrick with the apparently vast accomplishments of Unit 731, were appreciative of what the Japanese lack of “scruples” had achieved.

Military Legal Investigations

The Japanese scientists were worried about war crimes prosecutions then being pursued by the Adjutant General’s Office. 1 , p. 288 The difference between the scientific and legal investigations formed a striking contrast between Germany and Japan. In Germany, the very idea of “medical war crimes” originated among the scientists investigating the experiments, who then lobbied the legal staff to pursue prosecutions. In Japan, the legal staff was independently seeking evidence to prosecute war crimes, and the scientists were instrumental in stopping them.

The legal section received both anonymous and signed accusations against Ishii. In November, 1946, investigators wrote, “This information is being included in this report as another indication of mounting complaints concerning the alleged activities of General ISHII and his associates…principal among which are alleged to have been infecting Prisoners of War with glanders for experimental purposes.” 23

However, further investigation and prosecution was stymied by the Joint Chiefs of Staff as early as March 1947. They ordered the Adjutant General’s Office to seek the approval of military intelligence (G-2) for any further activities and to treat all related documents as top secret. It took another year for the final decision to be reached at the highest levels. The complicating factor was repeated requests from the Soviets, officially U.S. allies against Japan, to be allowed to interrogate the Japanese scientists. U.S. authorities were torn between the desire to deny the Russians access, even at the cost of an international incident, and their suspicion that allowing the Soviets to interrogate the Japanese with Americans present could reveal useful tips about the Soviets’ current knowledge of bacteriological warfare. 1 , pp. 291-300

A task force of the State-War-Navy Coordinating Committee (SWNCC), a high-level group overseeing the military occupation, indirectly admitted on August 1, 1947 their shaky ethical position. They acknowledged that Unit 731 “violate[d] the rules of land warfare,” 24 and that the Japanese experiments were similar to those for which Germans had been tried for war crimes. 1 , p. 301, 25

The task force now needed justification for refusing to prosecute. First they concluded that the evidence available was insufficient to document legal guilt. This was fallacious, both because it misrepresented the evidence then documented in Adjutant General reports, and also ignored the fact that confirmatory evidence was not being pursued specifically in response to military orders. Finally, the task force appealed to the same reasoning in the scientific reports: “The value to the U.S. of Japanese [biological warfare] data is of such importance to national security as to far outweigh the value accruing from ‘war crimes’ prosecution.” 1 , p. 301, 26 This conclusion amounted to a major coup for Ishii. When the full assessment of the Japanese data was finally completed, the Camp Detrick staff learned virtually nothing beyond what the Americans had already discovered by more “scrupulous” means. 1 , pp. 301-302

The SWNCC did not act on the task force’s recommendations for another six months. The Joint Chiefs’ final order placing all information under G-2 purview and ceasing all prosecutions against Ishii and associates was sent on March 13, 1948. By that time the Toyko war crimes trials against high Japanese military officials had been concluded, so the SWNCC review constituted a delaying tactic. 1 , p. 304

The aftermath to the cover-up of Japanese medical war crimes has been extensively documented elsewhere. 1 , 9 , 10 , 27 Unlike the U.S., the Soviet Union tried twelve captured Japanese military personnel from Unit 731 in Khabarovsk for war crimes and later published the proceedings. 1 , 10 , 28 U.S. authorities dismissed the proceedings as communist propaganda, though in hindsight the information presented was reasonably accurate. 10 , 29 The relatively light sentences given to the perpetrators, compared to the seriousness of the charges against them, suggested that the Soviets, like the Americans, traded leniency for access to data. 1 , 10

Discussion: Wartime Exigency

The Allies’ ethical decisions differed sharply in Germany and in Japan. The divergence can be explained partly by Japanese ruthlessness. Thompson was probably influenced by his direct contact with survivors of the concentration camps. The Japanese assured that no Allied personnel could encounter survivors of Unit 731, because they left no survivors. The women of Ravensbrück, who displayed their experimental wound scars, were among the most effective prosecution witnesses at Nuremberg; 7 the Japanese eliminated all potential witnesses.

Contrary to Harris’s claim that no ethical thinking appears in the American documents on Japan, there was no lack of ethical perception. 30 The Americans clearly saw a problem requiring ethical justification. Although today we regard their ethical thinking as seriously flawed; nevertheless, it was a form of ethical reasoning.

Previous analyses of the Nazi and Japanese transgressions and the U.S. cover-up have stressed national security concerns and nationalist ideology. 27 , 29 , 31 We suggest expanding this list to include wartime exigency .

National security, by itself, explains why basic human rights might be overridden by measures presumed necessary for national survival. This explanation, however, cannot fully account for the reasoning we encounter in post-war occupied Japan. Wartime exigency better captures the sense of urgency and the impatience with a full discussion of ethical options or with a fastidious inquiry into abuses of rights. National security may ultimately set the actors’ priorities, but cannot by itself explain the way decisions are made or not made. By contrast, “Don’t you realize that there’s a war going on?” better accounts for the reasoning recorded in the American documents. As Edmund Pellegrino summarized the rationalizations of the Nazi physicians, “To resist would have been treasonous; ethics must be subordinate to the demands of war.” 32 , p. 308

In its moral implications, wartime exigency might be seen as a darker version of carnival (when “carnival” is viewed as a general cultural phenomenon rather than as any specific, local celebration). 33 , 34 All year, people chafe under social constraints, which especially affect the underclasses. Once a year, people are able to break these constraints by overturning the usual social conventions, wearing masks to escape personal responsibility. Since even the underclasses have a stake in maintaining the social order, all are reassured that this overturning of convention is only temporary, and in a few days things will return to normal.

In peacetime, people who have strong cruel, sadistic impulses chafe at the moral constraints that forbid them from acting upon these impulses. People who have such impulses are often poorly equipped to engage in careful moral reasoning, so they may also be frustrated when, better fitted for casuistical reasoning, appear to get away with shady moral behavior. Wartime loosens unwelcome constraint for such individuals. They act out their impulses, citing the highest of motives -- patriotism. They feel free to thwart anyone who questions their morality, since “Don’t you know there’s a war going on?” cuts off all moral debate at the outset. Finally, should any guilt feelings arise, they can comfort themselves with the illusion that all this is only temporary--soon the war will be won, peace will ensue, and the normal moral order can be restored.

In another example of wartime exigency trumping human rights, David Rothman describes the Committee on Medical Research (CMR) that oversaw war-related science in the U.S. during 1941-45. The CMR accepted that research on human subjects required informed, voluntary consent. However, they applied that understanding inconsistently. They approved, for example, a study of an anti-malarial drug in 500 Illinois prisoners who were deliberately infected with the disease; one prisoner died. They proudly reported these experiments in press releases that lauded the inmates’ willingness to volunteer, stating, “these one-time enemies to society appreciate to the fullest extent just how completely this is everybody’s war.” 35 Any concerns about the prisoners’ ability to consent voluntarily to risky experiments were eclipsed by war-effort fervor.

Wartime exigency does more than simply prioritize national security over human rights. It urges toughness and decisiveness in decision-making, so that a moral blindness that would be seen as a deficiency in other times is instead seen as a virtue and a necessity.

Wartime exigency is worth labeling as a specific factor alongside national security particularly because of how our contemporary culture is seemingly engaged in a perpetual state of war. The war against the Axis powers was immediately supplanted by the Cold War, and the exigencies of that war were viewed as justifying the egregious actions taken in Japan. American society saw the end of the Cold War in 1989, but then declared an interminable War on Terror in 2001, and that most recent war has been implicated in a number of indefensible ethical and policy choices. 36


Thompson in Germany decided that the war was over, that the Germans had done terrible things under the pressure of racism, national security, and wartime exigency, and that future scientists in other nations would be tempted to commit similar crimes unless people decisively spoke out. The American scientists and policymakers in Japan decided that a new war was being waged and that national security and wartime exigency justified exonerating the perpetrators of Unit 731 and covering up their crimes.

By proposing wartime exigency as one ethical reason for the American cover-up, we do not mean to suggest that this reason operated without certain political and socio-cultural contexts, particularly the Cold War environment. 32 , 34 Another socio-historical element that has not been discussed, to our knowledge, is the role of racism. It might appear that racism played only a relatively minor part in American calculations. However, there was an obvious double standard in the American postwar responses to the experiments upon different nationalities. A U.S. tribunal in Yokohama in 1948 indicted nine Japanese physician-professors and medical students for conducting vivisection upon captured American fliers. 37 Two professors were sentenced to death and others to 15-20 years’ imprisonment, much harsher than the sentences of the Russian Khabarovsk trial. The war between Japan and the United States was not only a war of empires and powers, but also a war of races. 38 The military and political end of the Pacific war did not immediately end the racist socio-historical context.

One might object that our condemnation of events in Japan lacks ethical substance, since it might simply count as an argument of the form, “People did something years ago; today we would condemn what they did; therefore we must be right and they must be wrong.” We believe that we have defended against this objection by comparing two reactions to wartime experiments that were instituted by the same nation at roughly the same time. We have argued that the U.S. position in Japan would stand condemned as unethical if one merely applied the same standards that were then being applied in Germany.

Another objection might compare the tack taken by Americans in Japan with common law-enforcement practices, granting selective immunity to certain criminals as part of a wider effort to fight crime. There are several reasons why this analogy fails. First, if anyone were to adopt a strategy of granting immunity to gather confessions which would then lead to the prosecution of guiltier parties, it would have been the military legal authorities. But we have seen that it was the legal authorities who were seeking war crimes prosecution, while the scientific authorities were all for granting immunity. Second, and more telling, there was no effort to use any of these confessions as tools to prosecute other guilty parties. The overall goal of the U.S. effort in Japan was effectively to grant immunity to the entire Japanese medical profession, and to assure that no prosecution for “medical war crimes” ever took place. Far from being an acceptable strategy in a difficult situation, the U.S. cover-up met both ethical and legal criteria for “complicity after fact.” 27

According to the arguments we have put forth, it is essential to condemn both the Japanese war criminals and the Americans who covered up their crimes. But mere condemnation risks treating the Japanese perpetrators and the American officials as the radical “others” of humanity, our moral inferiors. To pursue a deeper understanding is not to rationalize or justify the atrocities but to identify the historical and ethical causes of why things went so terribly wrong. However faulty the ethical reasoning employed in the cover-up, by studying it we gain important insights into where such flawed reasoning may next be applied today and tomorrow.


We are grateful to Dr. Sheldon Rubenfeld and the Center for Medicine after the Holocaust for arranging the tour during which HB met PW and became aware of the importance of John Thompson in post-war events. PW acknowledges Wellcome Trust Grant No 096580/Z/11/A on research subject narratives and AHRC Grant AH/E509398/1 on Human Experiments under National Socialism. Griffin Trotter provided valuable comments in review of the manuscript.

Contributor Information

Howard Brody, Director, Institute for the Medical Humanities, University of Texas Medical Branch, Galveston, TX USA.

Sarah E. Leonard, Institute for the Medical Humanities, University of Texas Medical Branch, Galveston, TX USA.

Jing-Bao Nie, Bioethics Centre, Division of Health Science, University of Otago, New Zealand; (adjunct/visiting) Hunan Normal University and Peking University, China.

Paul Weindling, Department of History, Philosophy and Religion, Oxford Brookes University, Oxford, UK.

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Japan's Biological Warfare Project


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Unit 731 and Unit 100 were the two biological warfare research centres set up in spite of the Geneva Protocol of 1925 banning biological and chemical warfare.

Led by Lieutenant-General Ishii Shiro, 3,000 Japanese researchers working at Unit 731’s headquarters in Harbin infected live human beings with diseases such as the plague and anthrax and then eviscerated them without anesthesia to see how the diseases infected human organs.

Because of the Unit’s secret nature, there is no complete list of the experiments that were undertaken by Unit 731.

Testimonies from participants shed some light about parts of the experiments. An anonymous medical assistant described in a 1995 New York Times interview his first vivisection:

“The fellow knew that it was over for him, and so he didn’t struggle when they led him into the room and tied him down. But when I picked up the scalpel, that’s when he began screaming. I cut him open from the chest to the stomach, and he screamed terribly, and his face was all twisted in agony. He made this unimaginable sound, he was screaming so horribly. But then finally he stopped. This was all in a day’s work for the surgeons, but it really left an impression on me because it was my first time.”

But the Unit was not only infamous for its vivisections. Some prisoners sent to Unit 731 were taken outside and tied to stakes. The Japanese would then test new biological weapons such as plague cultures or bombs filled with plague-infested fleas on them.

Other studies involved exposing human guinea pigs, called ‘logs’ by the Japanese scientists, to their limits. Humans were locked inside pressure chambers to test how much the body could take before their eyes popped out.

Some human test subjects were taken outside during the harsh winter until their limbs froze off for the doctors to experiment how best to treat frostbite.

Since the Japanese army used poison gas during the war, one of the Unit 731’s mission was to develop a more potent poison gas, thus prisoners were subjected to poisoning.

In 1984, a graduate student at Keio Medical University in Tokyo found records of human experiments in a bookstore. The pages described the effects of massive dosages of tetanus vaccine. There were tables describing the length of time it took victims to die and recorded the muscle spasms in their bodies.

At least 3,000 people, not just Chinese but also Russians, Mongolians and Koreans, died from the experiments performed by Unit 731 between 1939 and 1945. No prisoner came out alive of the Unit’s gates. During the war, the Japanese Imperial Army used biological weapons developed and manufactured by Unit 731’s laboratory in Harbin throughout China, killing or injuring an estimated 300,000 people.

images of the Japanese experiment unit 731 in China

35 Rare Images of the Infamous Japanese Experiment Unit 731 in China

Table of Contents

  • 1 Japanese Experiment Unit 731: Rare Historical Images
  • 2 What was the Unit 731
  • 3.1.1 China Underground

Japanese Experiment Unit 731: Rare Historical Images

Unit 731 (731部隊), based in the Pingfang district of Harbin and led by the infamous Japanese microbiologist Shiro Ishii, was a covert biological warfare research and development unit of the Imperial Japanese Army that undertook human experimentation during the Second Sino-Japanese War (1937–1945) and World War II.

Featured image: A photograph released from Jilin Provincial Archives, which, according to Xinhua Press, “shows personnel of ‘Manchukuo’ attend a ‘plague prevention’ action which indeed is a bacteriological test directed by Japan’s ‘Unit 731’ in November 1940 at Nong’an County, northeast China’s Jilin Province.”

What was the Unit 731

At least 12,000 men, women, and children were killed during the experimentation conducted by Unit 731 at the camp based in Pingfang alone .

Related articles:   Names of members of infamous Unit 731 released by the National Archives of Japan , Rare images of the infamous Japanese experiment unit 731 in China – Second Part – Graphic content – Men Behind the Sun by Mou Tun-Fei (The film is a graphic depiction of the war atrocities committed by the Japanese at Unit 731 )

Prisoners of war were subjected to a range of brutal experiments without anesthesia, including vivisection. Researchers infected detainees with various diseases before performing invasive surgeries to remove organs. This was done to study the effects of diseases on the human body, with the operations carried out on living subjects to avoid the impacts of decomposition on the results.

experiment unit 731

In a series of inhumane tests, humans were also used as live targets to assess the effectiveness of grenades, flamethrowers, and germ-releasing bombs, as well as chemical and explosive weapons. These prisoners were positioned at different distances and orientations to gauge the lethality of these weapons.

Shiro Ishii, a prominent figure in these experiments, oversaw the injection of prisoners with disease inoculations under the guise of vaccinations. This allowed scientists to observe the progression of diseases like syphilis and gonorrhea, which were deliberately transmitted to both male and female prisoners without treatment, to study their effects.

Additionally, to further research into germ warfare, prisoners were infested with fleas to produce large quantities of disease-carrying fleas. Techniques of warfare included dropping bombs filled with plague fleas, infected clothing, and other contaminated materials on various targets. The dissemination of cholera, anthrax, and plague through these means is estimated to have resulted in the deaths of approximately 400,000 Chinese civilians. Tularemia was another disease tested on Chinese civilians in these horrific experiments.

Unit 731 images

Related article: Japanese officer performing seppuku during World War II

Source : Wikipedia , incredibleimages4u.blogspot.com , picturechina.com.cn , enviromental graffiti , http://xubaojun.blog.163.com

Topic: causes of unit 731, what did they do at Unit 731

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22 thoughts on “35 Rare Images of the Infamous Japanese Experiment Unit 731 in China”

We are a creation with the capacity to do great good and immense evil.

Today, Obama honors ww2 Japan…

That’s not wrong, in the end Japan suffered many casualties among the civilians…What we all should complain is the fact that americans didn’t punished many war criminals, like Shirō Ishii, the mastermind (or one of them) of the Unit 731. He died in 1959, and he didn’t pay for his crimes because americans wanted the data of the experiments! Of course the japanese government was guilty too, because they didn’t prosecute any of them. So OBama didn’t honor those war criminals, he honored the civil victims in Japan.

Did you know a lot of our modern medicine came from the findings of these experiments?

Maybe, but war criminals shoud pay for their crimes, if not with their lives, at least in some other ways.

What advances in modern medicine were advanced by these butchers? That I’d like to hear!!

It’s a long story. When you come in to an ER with extreme frostbite and they know exactly to treat you. They know exactly what frostbite does to the skin, tissues, etc. How it progresses and at what stage. Because of this information they could come up treatments. Where did they find out about the severe effects of frostbite? UNIT 731. Sad…but true. And this is just one example.

A lot of their experiments were to duplicate severe battle feild injuries. i.e. loss of limbs. Did you notice how much battle feild triage improved from WWII to the Korean War. Just 6 years seperate these two wars and yet medical surgical knowledge leaped for the MASH units. Where do you think this info came from?

What’re you talking about? Our modern medicine came from the findings of German experiments, not the Japanese.

The experiments were not done to save people in the future they were done to kill people in the most effective way. no noble goal just to make mass murder easy. The good came from doctors and scientists, who studied the craven acts

War Crimes are committed on both sides during War.

these are beyond “war crimes”… it is pure evil!

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I don’t know! do you? Do you have prove? they are researching to KILL, not to SAVE!!! Did you see the picture of all the naked kids? Any medicine worth that? Without humanity, what is left in life!!!

I’m sorry, but there’s absolutely no excuse, no justification that could justify what happened in Unit 731 and Unit 100. The cruelty and atrocity are beyond human understanding. I repeat THERE IS NO JUSTIFICATION WHATSOEVER for what took place in Harbin, China.

IT IS EVIL–SHEAR AND PURE EVIL. Shame to the Japanese who still try to cover it up or white wash their evil past !!!

im glad japan lost the war

It saddens me to hear this truth about the attrocities that were done in Unit 731. This is no different than in Germany. This is and was EVIL. I personally don’t care about the medical GAINS that have been achieved. Unfortunately EVERY EVIL has their way of justifying WHY they do what they do. Only GOD can forgive them. We must REMEMBER the reason WHY. Hitler; super race, Japanese; ??,. These days our younger generation only wants to whitewash the past. We are to learn from their past mistakes so they are NOT repeated.

everything about this point in time is a horror story. The really sad part of it all is China is literally doing things on this level in the name of organ transplants on demand as we speak today in 2020.

Are you people nuts, these VICTIMS are individuals with the exact same feelings of pain and terror and shock as you or I would experience, they probably had families and homes once, there is categorically no reason or excuse to put any human being through this kind of torture, I am utterly appalled and extremely upset by this atrocity and I believe that every one should be also, and as for medical knowledge we have found answers and treatments in ways that don’t destroy the profound right of every human to live and to live without being tortured

And by the way Crystal there is no such thing as supernatural beings, grow up

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The True Story Behind Japan’s WWII Human Experiment Division

The 20th Century is full of examples of man’s inhumanity to man. The horrors of the first World War early in the century set the stage for what was to become one of the darkest periods in human history. And no event serves as a more terrible reminder of how evil people can be than the atrocities that followed in the second World War.

The crimes of Nazi Germany in occupied territories and the industrial slaughter of the Holocaust resulted in the deaths of millions of people. But the second World War was truly a global conflict and evil was found everywhere it was fought.

Though they often get less popular attention than those of the Germans, the Japanese military’s crimes were certainly horrific. The occupation of Nanking by the Japanese Army led to a maelstrom of violence that lead to tens or possibly even hundreds of thousands of deaths among the residents of the city.

Like the Germans, the Japanese often treated the citizens in occupied territories with almost casual cruelty. Also like the Germans, the Japanese even exploited these people for horrific human experimentation . They even had a specialized unit they created to conduct these experiments: Unit 731.

The True Story Behind Japan&#8217;s WWII Human Experiment Division

The story of Unit 731 really began before the Second World War with the person who would eventually lead the unit’s activities, Shiro Ishii . Ishii was a medical officer in the Japanese military who specialized in studying infectious diseases. This kind of research was a popular subject for Japanese Army researchers like Ishii, who realized the importance of keeping troops healthy in the field. But Ishii also realized that infectious diseases could be turned against an enemy’s troops and began to advocate that the military look into developing biological weapons.

In 1930, Ishii petitioned the government for funding to form a research team that would study the effects of pandemic diseases. The government agreed and Ishii began work at the “Epidemic Prevention Research Laboratory,” where he claimed publicly to be working on ways to protect Japanese troops from diseases. This was actually true in one sense. Much of Ishii’s work was dedicated to researching effective ways to treat and prevent infectious diseases. However, Ishii’s actual intentions were always far darker. He wanted to learn which diseases would be the best candidate for weaponization.

With the permission of his direct superiors in the military, Ishii began to look for ways to turn his knowledge of preventing diseases towards finding ways to spread them. Ishii began testing various diseases on animals to see which spread quickly and killed efficiently in the hopes of finding the perfect biological weapon . However, Ishii felt that what he really needed to achieve his goal were human subjects. Because his research unit operated in Tokyo, ethical concerns and fears of containing the diseases he was testing prevented him from acquiring these subjects. However, events would soon provide him with the opportunity he needed.


The True Story Behind Japan&#8217;s WWII Human Experiment Division

In 1931, a Japanese military officer placed dynamite near the tracks of a Japanese-owned railway line in the region of Manchuria in North-East China. The resulting explosion did little actual damage, but officers in the Japanese Army seized the opportunity and blamed Chinese saboteurs for the attack that they themselves had engineered. Using the event as a pretext, they launched an invasion, quickly taking control of the region from the Chinese. The Chinese government, which didn’t want a war with Japan, offered little resistance and Japan set up a puppet government under the last Qing Emperor of China, Puyi .

Shiro Ishii recognized the opportunity to collect subjects from the civilian population of Manchuria and moved to Zhongma Fortress near the city of Harbin in Manchuria. There, Ishii organized a secret research group called the “Togo Unit” and began his research in earnest. During the occupation, the Japanese Army and secret police frequently arrested Chinese civilians and resistance fighters, as well as common criminals. Many of these prisoners ended up in Zhongma fortress, where they fell under the control of Ishii and the Togo Unit.

Ishii began to test the effects of various diseases on his human subjects. Under the guise of giving them vaccines, prisoners were injected with different bacteria or viruses to see how long it took for them to become infected. After the infection set in, the prisoners were monitored to see how the disease developed compared to other prisoners. In many cases, prisoners were then cut open while still alive to study the effects of the disease on their internal organs. Those who didn’t die from these tests were executed.

In 1934, a prisoner at Zhongma managed to overpower a guard and take his keys. He then freed forty of his fellow prisoners and scaled the walls of the fortress. Many of the prisoners attempting to escape were shot or recaptured, but a few managed to get away and spread the word of what was going on inside the prison. This escape and loss of secrecy lead Ishii and his superiors to close down their research at Zhongma and move to a new facility. There, the unit acquired the name by which it is most well-known: Unit 731. And there, they continued their horrific experiments.

Unit 731 was able to continue getting its supply of fresh subjects through the Japanese secret police, the Kempeitai. The Kempeitai arrested Chinese civilians on trumped-up charges of “suspicious activities” at the behest of Unit 731, which gave them instructions on whom to arrest. Ishii wanted to make sure that his subjects reflected the general population, so pregnant women, children, and the elderly were all arrested on these sorts of charges and brought to Ishii’s facility for tests on the effects of different diseases. And because Ishii wanted to test the effects of disease on different races of people, the large Russian community in Harbin was frequently targeted by the Kempeitei. In Ishii’s eyes, everyone was a potential subject for his twisted experiments.

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The True Story Behind Japan&#8217;s WWII Human Experiment Division

Ishii’s goal was always to find an effective biological weapon, so he investigated some of the most virulent diseases in human history. Many of his tests focused on the bubonic plague , which killed millions during the Middle Ages. He wanted to find ways to spread the plague quickly, which meant testing the best way to infect large numbers of people with the disease. Ishii ordered plague-infected fleas to be dropped from airplanes onto cities in China, leading to minor epidemics that killed thousands. In addition to fleas, Unit 731 dropped clothing or food infected with cholera and anthrax, leading to more epidemics and thousands of deaths.

But Unit 731 didn’t limit its research to just weaponizing disease, they also tested the effects of different injuries to the human body. Prisoners were often subjected to freezing temperatures to study the effects of frostbite, as guards beat them to determine how much feeling was left in their frozen limbs. The injuries were then left untreated to study the effects of gangrene, as the prisoner’s fingers or limbs began to rot and fall off. Other prisoners were subjected to experiments testing the effects of grenades from different ranges, and even flamethrowers. Obviously, few survived these types of tests.

Unit 731 was also very interested in venereal diseases, like syphilis or gonorrhea. Often, prisoners were infected with these diseases to test the effects and treatments. But these prisoners were also forced under threat of death to have sex with uninfected prisoners so that researchers could study how the diseases were transmitted from one person to another. They also wanted to study whether or not pregnant women could transmit a venereal disease to their fetus; thus women were sometimes forcibly impregnated for these tests.

Prisoners were also subjected to stranger experiments that reflect the callous disregard for human life shown by Unit 731. It was as though they simply wanted to satisfy their morbid curiosity. Prisoners were strapped into centrifuges that spun them at high speeds until they died. Others were injected with animal blood or seawater, simply to see how their body might respond. Still, others were bombarded with X-rays to study the effects of radiation. Some were simply buried alive or burnt to death. And others were denied food or water to see how long it took them to die.

Ultimately, Ishii’s experiments accomplished little. The Japanese never managed to develop a biological weapon that could turn the tide of the war. And Ishii’s attempts to pressure the Japanese military to use biological weapons in the Pacific were rebuffed several times. The only serious attack ever planned was to target the city of San Diego. However, this last desperate plan was aborted due to Japan’s surrender in 1945. After the surrender, Ishii was granted immunity by the American occupation forces in exchange for handing over his research. Ishii never stood trial for his crimes and lived out the rest of his days in Japan before dying of throat cancer years later. The fact that Ishii and other members of Unit 731 escaped prosecution truly rank among the worst failures of justice in history.

History Defined

Inside Unit 731 and Japan’s Human Experiments in WW2

From 1939 to 1945, the world witnessed the deadliest war in history, as over 30 countries wound together in acrimony, strife, and bloodshed, leading to a war that claimed the lives of more than 100 million people all over the world. History reveals that the war was replete with different subplots, each significantly ravaging our shared humanity.

But of all these battlefronts, the Pacific Theatre, hosting the most extended series of battles during WW2, stands tall as the epicenter of the action.

Historians recorded that Japan started the war when it launched an attack on Manchuria in 1931 and invaded China in 1937. This invasion was instantly followed by disturbances and upheavals that shook China’s very foundations, culminating in a civil war and famine that claimed the lives of over 63 million persons, lasting until China’s liberation in 1945.

Imperial Japan did unleash unspeakable terror on China during its occupation. Still, all these are nothing compared to the atrocities perpetrated in Unit 731 – the very center-point of Japanese biological warfare units that plunged the already genocidal war into newer depths of horror.

What started as a research and public health agency with a noble, innocent beginning descended into an abyss of terror when Unit 731 grew an assemblage for weaponized diseases that could have killed every living thing on earth multiple times over if deployed to its maximum strength.

This rather sordid shift in purpose was designed for the eternal suffering of captives as disease incubators and test subjects which very well served its purpose until 1945 when Unit 731 shut down operations.

But before then, Unit 731 had committed some of the most degrading and torturous human experiments in human history.

experiment unit 731

Frostbite Tests

Perhaps, assigning Yoshimura Hisato to Unit 731 marked the beginning of doomsday for the Chinese captives. Here was a physiologist with an uncanny obsession for hypothermia, whose curiosity had no limits and who had almost no regard for human life.

Attempting to improve on Maruta’s research on limb injuries, Hisato submerged the limbs of Chinese captives in water and ice and held them until the limb – arm or leg – had frozen with visible ice coatings on the skin. Eye witness accounts say the limbs sounded like wood when hit with a plank. But for Hisato, this was only the beginning. 

He attempted different methods to rewarm the frozen limbs as rapidly as possible. In some cases, he would douse the limb with hot water; other times, he would hold the limbs close to an open fire. And sometimes, he would leave the subject untreated overnight to examine how long it would take for the subject’s blood to break off the frost.

Maruta and the Throes of Vivisection

Established as a research unit, Unit 731 was preoccupied with investigating how disease and injury affect the fighting ability of armed forces. However, “Maruta,” an arm of the Unit, went rogue when it took up the research by a notch, breaking the defined bounds of medical ethics, though, at that point, it only observed injuries and disease courses on patients.

The project began with volunteers from the Army, but as the experiments scaled new highs and the supply of volunteers ran out, the Unit soon turned its attention to Chinese prisoners of war and captives. Consent became a thing of the past, and there was no limit to what researchers could do.

At this point, Unit 731 referred to their confined research subjects as “Murata” or “logs.” Needless to say, the study methods deployed for these experiments were highly dehumanizing.

Vivisection, one of the most common practices in those days, deserves special mention here. This was a process whereby human bodies were mutilated without anesthesia to conduct studies and experiments in living systems.

In those days, thousands of persons, primarily Chinese captives, elderly farmers, and children, who suffered diseases such as the plague and cholera, had their organs removed and examined.

This was mainly to study the possible effects of their various diseases before their body decomposes after death. In some instances, subjects had their limbs detached and reattached to another half of their body, while some had their limbs frozen, crushed, or cut off to study the spread of gangrene in the body.

When a subject’s body had exhausted its use, they would drive lethal injections into their body or shoot them even while some were buried alive. None of these Unit 731 subject captives survived this dehumanizing confinement, whether Chinese, Korean, Russian, or Mongolian.

Atrocious Weapons Tests

In every war, weapons superiority is a central talking point for superpowers. The Japanese knew this, only that they took it too seriously.

As the war raged, the effectiveness of weapons manufactured became a significant question and an area of interest to the Army. As part of efforts to determine the potency of their weapons, Unit 731 huddled captives together within a firing range.

It blasted shots at them from different ranges using Japanese weapons such as bolt-action rifles, Nambu 8mm, machine guns, grenades, and pistols. In assessing the varying levels of effectiveness, researchers compared wound patterns and depths of penetration to dying inmates and actual deaths.

Traditional weapons like knives, swords, and bayonets were equally studied, except in this case, the victims were usually bound. Unit 731 also tested flamethrowers on covered and open skin, while gas chambers were built at strategic unit facilities to expose test subjects to blister agents and nerve gas.

Victims were bound in one place as heavy objects dropped on them to study crush injuries, while test subjects were wound up and deprived of food and water to learn how long the average human can survive without water.

In most cases, these victims drank only seawater or were impaled with injections of mismatched animal or human blood to analyze the process of transfusion and clotting.

Prolonged exposure to x-ray sterilized and maimed thousands of research subjects while inflicting severe burns in cases where the emitting plates are miscalibrated or placed too close to the participants’ genitals, faces, or nipples.

Unit 731 also studied the effects of high G-forces on pilots and falling paratroopers. They loaded human beings into large centrifuges, spinning them at extremely high speeds until they lost consciousness or died, typically at 10 to 15 G’s. They found that young children were more tolerant of acceleration forces.

Syphilis Studies on War Captives

History has shown that venereal diseases have inflicted major disruptions on organized armies since ancient Egypt. In attempting to prevent similar occurrences, the Japanese military took an interest in studying the symptoms and treatments of syphilis.

For a start, doctors at Unit 731 infested test subjects with syphilis, withheld treatments, and observed the progress of the illness.

However, Salvarsan, a primitive chemotherapy agent and contemporary treatment in those days, was administered within a specified period to assess the side effects of the disease.

Male subject carriers of syphilis were asked to rape male and female captives to ensure the disease was effectively transmitted.

The infected prisoners were closely monitored to observe the onset and spread of the illness. Where the first exposure resulted in zero infection, more subjects were raped until the infection was established.

Rape and Systematic Pregnancy

You may consider the syphilis experiment far too outrageous, but it probably pales compared to the spate of rape and forced pregnancy that characterized Unit 731’s operations.

The most common instance includes female captives being raped and systematically impregnated so that trauma and weapon experiments could be carried out on them.

These women were advertently infected with life-threatening diseases, doomed to crush injuries, chemical weapons exposure, shrapnel injuries, and bullet wounds.

After this, Unit 731 doctors opened up the pregnant subjects and studied the effects of these injuries on the fetuses.

It appears the ultimate objective was to transpose the findings into contemporary medicine, but even if Unit 731 researchers had published these findings, the papers might not have survived the war.

Fleas and Plagues on Chinese Civilians

As time passed, it became clearer that Japan’s Unit 731 was driven by an ultimate mission to develop weapons of mass destruction by 1939, to ravage the Chinese people, and destroy Allied forces, if time permitted.

The Unit rounded up tens of thousands of captives caged across different facilities in Manchuria, which imperial forces had occupied for decades.

The Japanese infected these inmates with the most lethal virus and pathogens science has ever known. Prominent examples of such deadly pathogens include yersinia pestis, which causes the pneumonic and bubonic plague , and typhus, which the researchers systematically spread from one inmate to another to depopulate notable areas.

The doctors bred the most dangerous strains and monitored patients as they advanced through various stages, from symptoms to spread. When victims survived, they were shot, and the sickest were left to bleed on the mortuary table if they fell ill.

The doctors would take their blood would infect other captives, and the sickest from this group would be bled to transfect the deadliest strain to another group of prisoners.

Once, a member of Unit 731 pitched the idea that the sickest captives should be spread out on a slab with a line inserted into their carotid artery.

That’s not all – when the blood has been sucked out of their heart which would be too weak to pump more blood, a military officer will jump on the victim’s chest with his leather boots. The officer did this with so much force and vigor that it crushed the captive’s ribcage, and blood would spurt into a designated container.

One of the significant plagues bred by the Unit – plague bacillus – was built into a vastly lethal pathogen. The last set of subjects was exposed to an overwhelming huddle of fleas.

These fleas were packaged and sealed with clay bomb casings. On 4th October 1940, Japanese bombers released these casings, each containing 30,000 blood-sucking fleas that were initially exposed to the prisoners in a Chinese village called Quzhou.

According to eyewitnesses, the bombing was accompanied by fine crimson dust settling on different surfaces of the town and a succession of terrible flea bites that ravaged everyone present.

A series of eyewitness accounts agreed that at least 2,000 Chinese civilians died of the plagues foisted by these fleas, with 1,000 more deaths in a nearby village called Yiwu after sick railway staff carried the pathogen to this location. Unit 731 also employed anthrax to launch this attack, killing at least 6,000 people.

As the war tailed to an end, Japan tried to bomb America with the same fleas, but to no avail. But this was perhaps the beginning of the end for Unit 731 because by August 1945, Hiroshima and Nagasaki had been bombed, and the Soviet Army invaded Manchuria and annihilated the Japanese Army. The emperor then read his surrender memo over the radio and disbanded Unit 731.

The research records and reports were burnt, and all the data and information generated by the Unit in 13 years were equally destroyed.

Some researchers returned to everyday civilian life in Japan as if nothing had happened, with some venturing into academics and medicine.

Some quarters believe that vestiges of the experiment may have found their way into academia and may have played significant roles in building war and medical technologies today.

However, these ideas are mere conjectures that thrive on the possibility that bits of information from inside Unit 731 may have escaped the 1945 purge.

But here’s what we know for sure: World War 2 is such a deadly detour in human history, and at the very center of the Pacific Theatre in Manchuria, humanity was bent backward – a thousand times and over, and for 13 solid years.

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The Twisted Story Of Shiro Ishii, The Josef Mengele Of World War 2 Japan

Shiro ishii ran unit 731 and performed cruel experiments on prisoners until he was apprehended by the u.s. government — and granted full immunity..

A few years after World War I, the Geneva Protocol prohibited the use of chemical and biological weapons during wartime in 1925. But that didn’t stop a Japanese army medical officer named Shiro Ishii.

A graduate of Kyoto Imperial University and a member of the Army Medical Corps, Ishii was reading about the recent bans when he got an idea: If biological weapons were so dangerous that they were off-limits, then they had to be the best kind.

Shiro Ishii

Wikimedia Commons Shiro Ishii is often compared to the infamous Nazi doctor Josef Mengele, but he arguably had even more power over his human experiments — and did far more monstrous scientific research.

From that point on, Ishii dedicated his life to the deadliest kinds of science. His germ warfare and inhumane experiments aimed to place the Empire of Japan on a pedestal above the world. This is the story of General Shiro Ishii, Japan’s answer to Josef Mengele and the evil “genius” behind Unit 731.

Unit 731

Shiro Ishii: A Dangerous Youth

Born in 1892 in Japan, Shiro Ishii was the fourth son of a wealthy landowner and sake maker. Rumored to have a photographic memory, Ishii excelled in school to the point that he was labeled a potential genius.

Ishii’s daughter Harumi would later muse that her father’s intelligence might have led him to be a successful politician if he had chosen to go down that path. But Ishii chose to join the military at an early age, showing boundless love for Japan and its emperor all along the way.

Young Shiro Ishii

Wikimedia Commons From an early age, Shiro Ishii was believed to be a genius.

An atypical recruit, Ishii did well in the military. Standing six feet tall — well above the height of the average Japanese man — he boasted a commanding appearance early on. He was known for his spotlessly clean uniforms, his meticulously groomed facial hair, and his deep, powerful voice.

During his service, Ishii discovered his real passion — science. Specifically interested in military medicine, he worked tirelessly toward the goal of becoming a doctor in the Imperial Japanese Army.

In 1916, Ishii was admitted to the Medical Department of Kyoto Imperial University. In addition to learning both the best medical practices of the time and proper laboratory procedures, he also developed some strange habits.

He was known for keeping bacteria in petri dishes as “pets.” And he also had a reputation for sabotaging other students. Ishii would work in the lab at night after the other students had already cleaned up — and use their equipment. He would purposely leave the equipment dirty so the professors would discipline other students, which led them to resent Ishii.

But while the students knew what Ishii had done, he was apparently never punished for his actions. And if the professors somehow knew what he was doing, it almost seemed as if they were rewarding him for it.

It’s perhaps a sign of his growing ego that shortly after reading about biological weapons in 1927, he decided that he would become the best in the world at making them.

Shiro Ishii’s Immodest Proposal

Japanese Troops

Wikimedia Commons Special Naval landing forces of the Imperial Japanese Navy prepare to advance during the Battle of Shanghai in August 1937 — with gas masks firmly in place.

Shortly after reading the initial journal article that inspired him, Shiro Ishii began to push for a military arm in Japan that focused on biological weapons. He even directly pleaded with top commanders.

To truly grasp the scale of his confidence, consider this: Not only was he a lower-ranking officer suggesting military strategy, but he was also proposing the direct violation of relatively new international laws of war.

At the crux of Ishii’s argument was the fact that Japan had signed the Geneva agreements, but had not ratified them. Since Japan’s stance on the Geneva agreements was technically still in limbo, there was perhaps some wiggle room that would allow for them to develop bioweapons.

But whether Ishii’s commanders lacked his vision or nebulous grasp of ethics, they were skeptical of his proposal at first. Never one to take no for an answer, Ishii asked for — and ultimately received — permission to take a two-year research tour of the world to see what other countries were doing in terms of biological warfare in 1928.

Whether this signaled legitimate interest on the part of the Japanese military or simply an effort to keep Ishii happy is unclear. But either way, after his visits to various facilities across Europe and the United States, Ishii returned to Japan with his findings and a revised plan.

A Receptive Audience

Bombing Of Chongqing

Wikimedia Commons The Japanese soldiers bombed Chongqing, China from 1938 to 1943.

Despite the Geneva Protocol, other countries were still researching biological warfare. But, out of either ethical concerns or fear of discovery, no one had yet made it a priority.

So in the years preceding World War II, Japanese troops began to seriously consider investing their resources in this controversial weaponry — with the goal that their battle techniques would surpass all other countries on Earth.

By the time Ishii returned to Japan in 1930, a few things had changed. Not only was his country on track to wage war against China, nationalism as a whole in Japan burned a little brighter. The old country slogan of “a wealthy country, a strong army” was echoing louder than it had in decades.

Ishii’s reputation had also grown. He was appointed professor of immunology at the Tokyo Army Medical School and given the rank of major. He also found a powerful supporter in Colonel Chikahiko Koizumi, who was then a scientist at the Tokyo Army Medical College.

Chikahiko Koizumi

Wikimedia Commons Japanese army surgeon Chikahiko Koizumi. After World War II, he came under suspicion for being a war criminal, but he committed suicide before he could be properly investigated.

A veteran of World War I, Koizumi oversaw research into chemical warfare beginning in 1918. But around this time, he almost died in a lab accident after being exposed to a chlorine gas cloud without a gas mask. After his full recovery, he continued his research — but his superiors placed a low priority on his work at the time.

So it’s no surprise that Koizumi saw himself reflected in Shiro Ishii. At the very least, Koizumi saw someone similar enough to him who shared his vision for Japan. As Koizumi’s star continued to rise — first to Dean of the Tokyo Army Medical College, then to Army Surgeon General, then to Japan’s Minister of Health — he made sure that Ishii moved up along with him.

For Ishii’s part, he certainly enjoyed the praise and promotions, but nothing seems to have been more important to him than his own self-aggrandizement.

Ishii’s public work consisted of researching microbiology, pathology, and vaccine research. But as all those in the know understood, this was only a small part of his actual mission.

Unlike his student years, Ishii was rather popular as a professor. The same personal charisma and magnetism that had won over his teachers and commanders also worked on his students. Ishii often spent his nights out drinking and visiting geisha houses. But even while inebriated, Ishii was more likely to go back to his studies than to go to bed.

This behavior is telling on two counts: It shows the kind of obsessive man Ishii was, and it explains how he was able to persuade others to help him with his deranged experiments after he began working in China.

A Secret, Sinister Facility

Unit 731 Germ Test

Xinhua via Getty Images Unit 731 personnel conduct a bacteriological trial upon a test subject in Nongan County of northeast China’s Jilin Province. November 1940.

Following the invasion of Manchuria in 1931 and the establishment of the puppet client state Manchukuo shortly thereafter, Japan utilized the region’s resources to fuel its industrialization efforts.

Like the attitudes of Americans during the “Manifest Destiny” period of expansion, many Japanese soldiers saw the people living in the area as obstacles. But to Shiro Ishii, these residents were all potential test subjects.

According to Ishii’s theories, his biological research would require different types of facilities . For instance, he established a biological weapons facility in Harbin, China, but quickly realized that he wouldn’t be able to freely conduct involuntary human research in that city.

So he simply began to put together another secret facility that was about 100 kilometers south of Harbin. The 300-home village of Beiyinhe was razed to the ground to make way for the site, and local Chinese laborers were drafted to construct the buildings.

Here, Shiro Ishii developed some of his barbaric techniques, foreshadowing what would come in the notorious Unit 731.

Harbin Bioweapon Facility

Wikimedia Commons Unit 731’s Harbin facility was built on Manchurian land conquered by Japan.

The sparse records from the Beiyinhe facility offer a sketch of Ishii’s work there. With up to 1,000 prisoners crammed into the facility, the test subjects were a mixed group of underground anti-Japanese workers, guerrilla bands who harassed the Japanese, and innocent people who unfortunately got caught in a roundup of “suspicious persons.”

A common early experiment was drawing blood from prisoners every three to five days until they were too weak to go on, and then killing them with poison when they were no longer considered valuable to research. Most of these subjects were killed within a month after their arrival, but the number of total victims in the facility remains unknown.

In 1934, a prisoner rebellion broke out as the soldiers celebrated the Mid-Autumn Festival. Taking advantage of the guards’ drunkenness and the relatively lax security, some 16 prisoners were able to successfully escape. This is the main reason why we know what we do about that facility.

Despite the extreme risk to the security and secrecy of the operation, it’s possible that experiments continued at that site as late as 1936, before it was officially shut down in 1937.

Ishii, for his part, did not seem to mind the closure. He was already getting started with another facility — which was far more sinister.

The Josef Mengele Of Japan

Children At Unit 731

Xinhua via Getty Images Unit 731 researchers conduct bacteriological experiments on captive child subjects in Nongan County of northeast China’s Jilin Province. November 1940.

Shiro Ishii is often compared to Josef Mengele, the German doctor known as the “Angel of Death,” who conducted sinister experiments in Nazi-occupied Poland.

The infamous Auschwitz-Birkenau concentration camp was a complex that killed its prisoners as part of its design. While many victims were executed in gas chambers, others were reserved for Mengele and his twisted medical experiments.

As an SS officer and member of the Nazi elite, Mengele had the authority to determine the fitness of prisoners, recruit imprisoned medical professionals as assistants, and force inmates into becoming his test subjects.

But unlike Ishii, Mengele was more limited in his power over the camp and in the effectiveness of his research. Auschwitz had been built to produce rubber and oil, and Mengele used the environment to conduct pseudoscience. His work fell under the guise of genetics , but it was often little more than pointless and cruel acts of sadism.

In many ways, Ishii had more control over his human subjects. His research was also more scientific — and monstrous. Just about all the horrors that occurred in the facilities had been thought up by Ishii — with the intention of turning human beings into data.

Expanding and building upon his earlier efforts, Ishii designed Unit 731 to be a self-sufficient facility, with a prison for his human subjects, an arsenal for making germ bombs, an airfield with its own air force, and a crematorium to dispose of human remains.

In another part of the facility were the dormitories for Japanese residents, which included a bar, library, athletic fields, and even a brothel.

But nothing at the complex could compare to Ishii’s house in Harbin, where he lived with his wife and children. A mansion left over from the period of Russian control over Manchuria, it was a grand structure that was remembered fondly by Ishii’s daughter Harumi. She even likened it to the home in the classic film Gone With The Wind .

Shiro Ishii And The Experiments At Unit 731

Unit 731 Experiment

Xinhua via Getty Images The frostbitten hands of a Chinese person who was taken outside in winter by Unit 731 personnel for an experiment on how to best treat frostbite. Date unspecified.

If you know the name Unit 731, then you probably have some idea of the horrors that unfolded at Ishii’s facility — believed to be set up around 1935 in Pingfang. Despite decades of cover-up, stories of the cruel experiments that took place there have spread like wildfire in the age of the internet.

However, for all the discussion of freezing limbs, vivisections, and high-pressure chambers, the horror that tends be ignored is Ishii’s inhumane reasoning behind these tests.

As an army doctor, one of Ishii’s primary goals was the development of battlefield treatment techniques that he could use on Japanese troops — after learning just how much the human body could handle. For example, in the bleeding experiments, he learned how much blood the average person could lose without dying.

But at Unit 731, these experiments kicked into high gear. Some experiments involved simulating real-world conditions.

For example, some prisoners were placed in pressure chambers until their eyes popped out so that they could demonstrate how much pressure the human body could withstand. And some prisoners were injected with seawater to see if it could work as a replacement for a saline solution.

The most horrifying example touted around the internet – the frostbite experiment — was actually pioneered by Yoshimura Hisato, a physiologist assigned to Unit 731. But even this test had a practical battlefield application.

Unit 731 researchers were able to prove that the best treatment for frostbite was not rubbing the limb — the traditional method up until that point — but instead immersion in water a bit warmer than 100 degrees Fahrenheit (but never hotter than 122 degrees Fahrenheit). But the way they came to this conclusion was horrific.

Unit 731 researchers would lead prisoners outside in freezing weather and leave them with exposed arms that were periodically drenched with water — until a guard decided that frostbite had set in.

Testimony from a Japanese officer revealed that this was determined after the “frozen arms, when struck with a short stick, emitted a sound resembling that which a board gives when it is struck.”

When the limb was struck , this sound would apparently let the researchers know that it was sufficiently frozen. The frostbite-affected limb was then amputated and taken to the lab for study. More often than not, the researchers would then move on to the prisoners’ other limbs.

When prisoners were reduced to heads and torsos, they were then handed over for plague and pathogen experiments. Brutal as it was, this process bore fruit for Japanese researchers. They developed an effective frostbite treatment several years ahead of other researchers.

As with Mengele, Ishii and the other Unit 731 doctors wanted a wide sample of subjects to study. According to official accounts, the youngest victim of a temperature-changing experiment was a three-month-old baby .

The Brutality Of Weapons Testing

Unit 731 Medical Table

Xinhua via Getty Images A Unit 731 doctor operates on a patient that is part of a bacteriological experiment. Date unspecified.

Weapons testing at Unit 731 took several distinct forms. As with medical research, there were “defensive” tests of new equipment, such as gas masks.

Researchers would force their prisoners to test out the effectiveness of certain gas masks in order to find the best kind among the pack. Although unconfirmed, it is believed that similar testing led to an early version of the bio-hazard protection suit.

In terms of offensive weapons tests, these tended to fall under two different categories. The first was the deliberate infection of prisoners to study disease effects and to select suitable candidates for weaponization.

In order to better understand the impacts of each disease, researchers did not provide prisoners with treatment and instead dissected or vivisected them so that they could study the impact of the diseases on the internal organs. Sometimes, they were still alive while they were being cut open.

In a 1995 interview, one anonymous former medical assistant in a Japanese Army unit in China revealed what it was like to cut open a 30-year-old man and dissect him alive — without any anesthetic.

“The fellow knew that it was over for him, and so he didn’t struggle when they led him into the room and tied him down,” he said. “But when I picked up the scalpel, that’s when he began screaming.”

He continued, “I cut him open from the chest to the stomach, and he screamed terribly, and his face was all twisted in agony. He made this unimaginable sound, he was screaming so horribly. But then finally he stopped. This was all in a day’s work for the surgeons, but it really left an impression on me because it was my first time.”

The second type of offensive weapons testing involved the actual field testing of various systems that dispersed diseases. These were used against prisoners within the camp — and against civilians outside of it.

Ishii was diverse in his exploration of disease dispersal methods. Inside the camp, prisoners infected with syphilis would be forced to have sex with other prisoners who weren’t infected. This would help Ishii observe the onset of the disease. Outside the camp, Ishii gave other prisoners dumplings that were injected with typhoid and then released them so they could spread the disease.

He also passed out chocolates filled with anthrax bacteria to local children. Since many of these people were starving, they often didn’t question why they were receiving this food and unfortunately assumed it was just an act of kindness.

Sometimes, Ishii’s men would use air raids to drop innocuous items like wheat and rice balls and strips of colored paper above nearby cities. It was later discovered that these items were infected with deadly diseases.

But as horrific as these attacks were , it was Ishii’s bombs that truly placed him at the top of all other biological weapons researchers.

A “Gift” To Mankind

Germ Warfare

Xinhua via Getty Images Japanese personnel in protective suits carry a stretcher through Yiwu, China during Unit 731’s germ warfare tests. June 1942.

Ishii’s plague bombs carried an unusual payload. Instead of the usual metal containers, they would use containers made of ceramic or clay so that they would be less explosive. That way, they would be able to properly release plague-infected fleas on countless people.

Unable to improve off of the traditional means of spreading the “Black Death,” Ishii decided to skip the rat middleman. When his bombs exploded, the surviving fleas would quickly escape, seeking out hosts to feed on and spread the disease.

And that’s exactly what happened in China during World War II. Japan dropped these bombs on both combatants and innocent civilians in multiple towns and villages.

But Ishii’s master plan, “Operation Cherry Blossoms at Night,” intended to use these weapons against the United States .

If this plan would’ve succeeded, about 20 of the 500 new troops who arrived in Harbin would’ve been taken toward southern California in a submarine. They would’ve then manned an onboard plane and flown it to San Diego. And plague bombs would’ve then been dropped there in September 1945.

Thousands of disease-riddled fleas would’ve been deployed, as the troops took their own lives by crashing somewhere onto American soil.

However, America’s atomic bombings happened before this plan came to fruition. And the war ended before the operation was even fully mapped out. But ironically enough, it was America’s interest in Ishii’s research that ultimately saved his life.

In August 1945, shortly after the atomic bombings of Hiroshima and Nagasaki, the order came to destroy all evidence of the activities at Unit 731. Shiro Ishii sent his family ahead by railroad, remaining behind until his infamous facilities were destroyed.

The exact number of people killed by Unit 731 and its related programs remains unknown, but estimates usually range from about 200,000 to 300,000 (including the biological warfare operations). As for deaths due to human experimentation, that estimate typically ranges around 3,000. By the end of the war, any remaining prisoners were speedily killed off.

Although Ishii was also ordered to destroy all documentation, he carried some of his lab notes out of the facility with him before going into hiding in Tokyo. Then, the American occupation authorities paid him a visit.

Throughout the war, vague reports from China about unusual outbreaks and “plague bombs” had not been taken very seriously until the Soviets took Manchuria from the Japanese. By that point, the Soviets knew enough to have a vested interest in finding and securing General Ishii to “interview” him about his infamous research.

For better or for worse, the Americans got to him first. According to Ishii’s daughter Harumi, the American officers used her as a transcriber as they interrogated her father about his work.

At first, he played coy, pretending not to know what they were talking about. But after he secured immunity, protection from the Soviets, and 250,000 yen as payment, he began to talk.

All told, he’d revealed 80 percent of his data to the United States by the time of his death. Apparently, he took the other 20 percent to his grave.

A Deal With The Devil

Unit 731 Bombs

Wikimedia Commons Unit 731 bombs on display at a museum on the site of where the Harbin bioweapon facility used to be.

In order to protect Ishii and maintain a monopoly on his research, the United States kept its word. The crimes of Unit 731 and other similar organizations were suppressed, and at one point they were even labeled “Soviet Propaganda” by American authorities.

And yet, a “top secret” cable from Tokyo to Washington in 1947 revealed: “Experiments on humans were … described by three Japanese and confirmed tacitly by Ishii. Ishii states that if guaranteed immunity from ‘war crimes’ in documentary form for himself, superiors, and subordinates, he can describe program in detail.”

To put it plainly, American authorities were eager to learn the results of experiments that they weren’t willing to perform themselves. That’s why they granted him immunity.

Although some of the research from Ishii was valuable, American authorities didn’t learn nearly as much as they thought they would. And yet they kept their end of the bargain. Shiro Ishii lived out the rest of his days in peace until he died of throat cancer at the age of 67.

Years after the agreement, North Korea made a startling allegation that the United States had dropped plague bombs on them during the Korean War.

And so a group of scientists from France, Italy, Sweden, the Soviet Union, and Brazil — led by a British embryologist — toured the affected areas to collect samples and issue a verdict in the 1950s.

Allegations Of American Biological Warfare

Wikimedia Commons A page from the International Scientific Commission for the Facts Concerning Bacterial Warfare in China and Korea. Allegations that America used biological warfare during the Korean War remain controversial to this day.

Their conclusion was that germ warfare had indeed been used as North Korea claimed. Officially, this is also “Soviet Propaganda,” according to the United States. Or is it?

With a clear answer still missing, we are left with uncomfortable questions. Consider the following: In 1951, a now-declassified document showed that the U.S. Joint Chiefs of Staff issued orders to begin “large scale field tests… to determine the effectiveness of specific BW [bacteriological warfare] agents under operational conditions.” And in 1954, Operation “Big Itch” dropped flea bombs at the Dugway Proving Ground in Utah.

With that in mind, what is more likely? Are these actions coincidental to the Chinese and Soviets using part of the truth that they knew in an attempt to embarrass the Americans? Or, did someone secretly give the order to bring Shiro Ishii and his men out of retirement?

In any case, one thing is clear. Shiro Ishii never faced justice and died a free man in 1959 — all thanks to the United States deal with the Devil.

After reading about Shiro Ishii, the unhinged mind behind Unit 731, learn the full story of Operation “Cherry Blossoms at Night.” For a glimpse of what the operation may have looked like, check out the mysterious “Battle of Los Angeles” that may have been started by a Japanese balloon bomb.

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The human test subjects of Unit 731 were criminals, political prisoners, Communists, or civilians—usually pregnant women, children, and the elderly—who were considered useful for experiments and were rounded up under trumped-up charges. Seventy percent of these victims were Chinese, while others were Korean, Mongolian, and Russian, and a few might have been Allied prisoners of war. They were called marutas by the researchers, or “logs”, because the local Manchurians were told that the facility was a lumber mill. Research findings discovered at Unit 731 were occasionally published in peer-reviewed scientific journals, where the articles claimed the experiments had been performed on Manchurian monkeys.

Whether these prisoners were called logs or monkeys, their human suffering was immense. One of the most common experiments at Unit 731 was the vivisection of diseased bodies. Researchers found the most virulent strains of disease by infecting prisoners, usually by injecting them with “vaccines” or feeding them contaminated food, and killing those prisoners who recovered quickly from their illnesses. They then injected the more potent bacteria and viruses from the sickest prisoners into the next “generation” of victims. For researchers who wanted to view a more natural progression of disease, some prisoners were kept locked in cages in the same room as plague-infested mice and fleas to see how long it took for them to become infected. The prisoners were then sliced open so that researchers could see how the disease affected living organs. This vivisection was done without anesthetic, to ensure results untainted by any external factors. Vivisections were also commonly performed on pregnant women—many of whom were pregnant by rape.

The researchers were especially interested in the pregnancies of women with syphilis. The Japanese military was struggling to combat the syphilis sweeping through its ranks, likely due to the rape of civilian women and of the comfort women forced to service the military. At first the researchers tried to inject prisoners with syphilis, but seeing that this yielded few results, they turned to raping them. Two prisoners, one infected with syphilis, were placed in a room together along with armed guards and made to have sex with each other. Once the previously healthy partner contracted syphilis, they would be inspected periodically to see the progression of the disease, culminating in a vivisection to see what syphilis did to the organs and—in the case of pregnant prisoners—the baby. Vivisection was practiced on Chinese citizens at many other government-sponsored research facilities besides Unit 731. For a time, it was considered the most effective way to train young Japanese medical students to perform surgeries correctly.

Unit 731 researchers also experimented with methods of treating frostbite. Prisoners were taken outside in freezing weather, sometimes after being dipped in water, and kept there until their limbs were frozen solid. Artificial cool air currents accelerated the freezing. A Japanese officer who watched one of these experiments stated later that frostbite was considered achieved if, when struck, the prisoner’s limbs made a sound like a wooden board. Sometimes prisoners were left to thaw, their arms and legs turning gangrenous until they rotted. Usually, however, frostbite victims were immersed in water at various temperatures to see which temperatures cured frostbite the fastest. It’s from these tests run by Unit 731 that the world knows the most effective way to deal with frostbite—not to rub the affected limbs, but to immerse them in water between 100 and 122 degrees Fahrenheit.

But the main research aim of Unit 731 was to develop the most effective biological warfare weapons. At a testing ground called Anda, prisoners were lashed to stakes and suffocated with poison gas or forced to wait while planes dropped plague bombs—bombs full of plague-infested fleas—over them. Prisoners were also used to test the effective range of flamethrowers, chemical weapons, and bombs, including bacteriological bombs. The resulting shrapnel of these weapons was often infected with various diseases, so that researchers could discover how long it would take people to die from being hit by flying shrapnel only. Unit 731 helped develop balloon bombs, which were sent to float across the Pacific to the United States and cause destruction and terror. Only a few ever actually arrived in the United States and went off, and while American news outlets were requested not to report on these bombs for fear of causing mass hysteria, there were at least seven verified American victims.

Unit 731 was also instrumental in planning an army operation which was never carried out, Cherry Blossoms at Night, which involved infecting San Diego with the bubonic plague using kamikaze pilots. This operation was halted in large part, it seems, by the intervention of Hideki Tojo—a man the United States later hanged for his other war crimes. Other contributing factors to the failure of Cherry Blossoms at Night were the Japanese surrender in August 1945 (Cherry Blossoms at Night was planned for September) and the necessity near the end of the war for the Japanese to focus on defense rather than offense.

China wasn’t so lucky. Using knowledge developed from Unit 731 tests, the Imperial Japanese Army created plague bombs and had airplanes spray diseases like bubonic plague, cholera, and anthrax over Chinese cities, killing hundreds of thousands of people. Plague outbreaks, for example, were reported in Changde in north-central China and Ningbo in eastern China. Between three and four hundred thousand Chinese people are estimated to have been killed by this method of biological warfare.

Unit 731’s other experiments included injecting prisoners with animal blood and horse urine, heating them until they died, spinning them with centrifuges until they died, and locking them in pressure chambers until their eyes popped out. It’s estimated that about 3,000 people died from the tortures they underwent at Unit 731.

After the war, the American government helped cover up many of the atrocities the Japanese military committed during the war. The masterminds of Unit 731 were granted immunity during the Tokyo Trials in exchange for handing over what data existed on the Unit 731 experiments. Many of those affiliated with Unit 731 enjoyed long and illustrious medical careers. Three Unit 731 researchers became the president of the Japan Medical Association, the head of the Japan Olympic Committee, and the Governor of Tokyo.

In April 2018, a nearly complete list of the 3,607 people who were employed by Unit 731 on January 1, 1945 was released to the public. Katsuo Nishiyama, professor emeritus of Shiga University of Medical Science, is attempting to use the list to declare the university degree of one of Unit 731’s officers illegitimate. It seems likely the experiments which this man oversaw for his dissertation were performed on Unit 731 prisoners, rather than on animals as he had claimed. Many hope that the release of this list will be a major step towards Japan openly condemning its wartime atrocities.
For more information about Unit 731, please check out some of the sources used to write this article. Additionally, Pacific Atrocities Education has produced a book about Unit 731. You can view it here:  

Newsweek, 17 Apr. 2018, www.newsweek.com/identities-japanese-war-crimes-unit-killed-pows-released-889544. Factories of Death: Japanese Biological Warfare, 1932-1945 and the American Cover-Up. Routledge, 2002. The New York Times, The New York Times, 17 Mar. 1995, www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html. Theodicy--Through the Case of "Unit 731". Boston University, Dec. 2003, people.bu.edu/wwildman/WeirdWildWeb/courses/thth/projects/thth_projects_2003_parkeun.htm. The History Teacher, vol. 48, no. 2, Feb. 2015, pp. 271–294., www.societyforhistoryeducation.org/F15Preview.html. Newsweek, 17 Apr. 2018, www.newsweek.com/identities-japanese-war-crimes-unit-killed-pows-released-889544. NPR History Department, National Public Radio, 20 Jan. 2015, www.npr.org/sections/npr-history-dept/2015/01/20/375820191/beware-of-japanese-balloon-bombs. Unit 731: The Japanese Army's Secret of Secrets. London, 1989.




The morally deficient leadership in the US who condoned the pardon of these butchers should be roundly condemned. MacArthur, Truman and the Joint Chiefs should be ashamed of themselves. But in brainwashed America who is going to bring this out? Our national debate focuses on the trivial and superficial. These issues will forever be silenced in the interests of National Security....

In humanity those who do such atrocities “may” get away with them, but not on God’s Judgment Day. They will answer for their crimes to the ultimate judge

interested in how people can do what they do to each other

Some human beings have a completely horrific way of treating others. The fact that they are unable to have compassion for others is a massive problem. Im unable to be able to express how disturbing, disgusting and horrific humans are capable of such behaviour. The fact that governments around the world hide and covered up these types of actions for there own use is extremely difficult and scary to see. When this is what is considered ok . Makes me wonder what else is going on behind closed doors and what governments are attempting to hide from the population!!

Your last words, "Makes me wonder..".. Wonder YES, want to know NO, because the truth about many (all?) things is not what we thought or hope it is. Look at the world last 3yrs changing faster then a rollercoaster and not in a positive way. It cause stress to humans, thats why many are depressed or even worst did end their lives. Same story with the vaccin everybody should take and completely safe our gouverments said. Not one generation has to deal with what we do now, violation about humanrights is not far away in foreign countries, it is here, there, everywhere because WE MUST follow the new rules and the plan to create chaos and sepperated did worked instead of us stay together strong and fight back. We, the people are like cheeps now, follow without thinking. If you buy something to eat or drink the first time, you read the ingrediants whats all inside, but when you take a needle inside your arm to put some vaccin inside your body you believe the man or female on your television. You give your live to thos who dont give a *** about you. In here we have a ex politici who opend a shop, we did chat, he said, if you KNOW whats truely happend in politics, maybe you get crazy because you cant handle the situation, just have to deal with it.

The Whizzinator Touch is a synthetic urine device that includes a prosthetic. The device is made up of an ultra-secure belt that goes around your waist and legs,

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100,000 Pages Declassified in Search for Japanese War Crimes Records Press Release · Friday, January 12, 2007

New iwg volume and records guide on japanese records now available.

The declassification is a result of a thorough investigation by several U.S. government agencies for classified records remaining in their files, pursuant to the requirements of the Nazi War Crimes and Japanese Imperial Government Records Disclosure Acts. The declassified records include a range of materials from the Office of Strategic Services (OSS), CIA, the State Department, Army Intelligence, FBI, and other agencies, and cover many aspects of the Pacific conflict and postwar relations between the United States and Japan. In general, however, only a small portion of these records specifically pertains to Japanese war crimes. The records are open and available at the research room of the National Archives at College Park, Maryland.

As a result of the interagency government search, the IWG learned that there were millions of pages of previously declassified or unclassified records related to Japanese war crimes already available at the National Archives. The U.S. Government has been steadily releasing records with information about Japanese war crimes since the 1950s, with the bulk of the material declassified by the 1970s. Only a small portion of these records, however, have been examined by researchers, as they are spread across various collections.

IWG Chair and Archivist of the United States, Allen Weinstein, said, “The new volume and records guide will become invaluable tools to researchers and historians of the Pacific Theater of World War II. These new resources will help scholars bring to light a fuller understanding of Japan’s wartime actions.”

Researching Japanese War Crimes Records: Introductory Essays and the finding aid are the first major resources available to researchers interested in these records. The volume provides readers with a historiographic context for both newly declassified records and for records that have been available but largely unused. Included is new information about the capture, exploitation and controversial return to Japan of Imperial Government records. The voluminous electronic finding aid, Japanese War Crimes and Related Topics: A Guide to Records at the National Archives , will help researchers identify records, providing an entryway into a vast archive of records that have been underused. Free copies of the printed book and finding aid (on CD-ROM) can be ordered by by contacting us and are available while supplies last.

Since 1999, the IWG has declassified and opened to the public an estimated 8 million pages of documents. The once secret records are helping to shape our understanding of the Holocaust, war crimes, and World War II and postwar activities of U.S. and Allied intelligence agencies. The IWG has issued two reports to Congress (in October 1999 and March 2002 ), and it issues news releases and occasional newsletters . U.S. Intelligence and the Nazis , a 15-chapter book prepared by the IWG team of historians, was published in April 2004. More information can be found on the IWG web page .

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experiment unit 731

The Truth of Unit 731: Elite medical students and human experiments (2017). An NHK Documentary broadcast in 2017, including paper materials, recording tapes, and interviews to former members and doctors who have implemented experiments in Unit 731. In The Blacklist, the episode "General Shiro" is a reference to Shirō Ishii.

Updated March 12, 2024. These six "experiments" by Unit 731 rank among some of the most horrifying war crimes ever committed — and they went virtually unpunished. Xinhua via Getty Images Unit 731 personnel conduct a bacteriological trial upon a test subject in Nong'an County of northeast China's Jilin Province.

Unit 731, a Japanese Imperial Army program, conducted deadly medical experiments and biological weapons testing on Chinese civilians during WWII. Thousands of prisoners were killed in cruel experiments, and perhaps hundreds of thousands more died from biological weapons testing. The true extent of Unit 731's actions was shielded from public ...

For more than seven decades those atrocities, including the use of human beings for medical experiments, have been common knowledge. Far less known is the wholesale slaughter of hundreds of thousands of Chinese by a Japanese organization known as Unit 731. Established for the purpose of developing biological and chemical weapons, Unit 731 ...

Unit 731, short for Manshu Detachment 731, was a unit of the Imperial Japanese Army that engaged in unethical and deadly human experimentation, including testing of biological and chemical weapons on human populations, during the Second Sino-Japanese War (1937-1945) and World War II.Based in Japanese-occupied China, it was responsible for some of the most notorious war crimes committed by ...

Unit 731, located in Harbin, China, was a secret Japanese project that carried out human medical experiments during the 1930s and 1940s. ... none of those involved with the experiments at Unit 731 were ever punished for their crimes. Instead, after war's end, many re-entered society and went on to have very successful careers in their fields. ...

The Aims of Unit 731 and Shiro Ishii's Research. The horrific experiments carried out within the walls of Unit 731 were not just a case of cruelty for cruelty's sake. The aim of Shiro Ishii's research was the development of an effective chemical and biological weapons program that could turn the tide of the war in Japan's favor.

The experiments conducted at Unit 731 and its satellites can be classified into the following broad categories: Vivisections for training new Army surgeons: These were performed at army hospitals in China using many Chinese prisoners. The doctors were trained to perform appendectomies and tracheotomies; prisoners were shot, then doctors removed ...

Unit 731 was a vehicle for the systematic torture and murder of countless innocents under the pretext of scientific advancement and national progress. Under Ishii's leadership, Unit 731 began a macabre initiative known as Maruta, wherein human beings were ruthlessly subjected to experimentation.

Unit 731 , short for Manchu Detachment 731 and also known as the Kamo Detachment and the Ishii Unit, was a covert biological and chemical warfare research and development unit of the Imperial Japanese Army that engaged in lethal human experimentation and biological weapons manufacturing during the Second Sino-Japanese War (1937-1945) and World War II. Estimates vary as to how many were ...

Due to an American cover-up, the details behind Unit 731's human experimentation were slow to be revealed. The recent literature discloses the gruesome details of the experiments but characterizes the human trials as crude in nature. Further, there is a lack of clarity as to how human trial results were extrapolated for use in real world ...

Unit 731 was established first in 1932 as a small group of five scientists interested in biological weapons, and was expanded around 1936 when Shiro Ishii was given full command of the unit. ... Other experiments included prisoners being locked inside a pressure chamber to test how much pressure the body can handle before their eyes started ...

The Unit 731 experiments involved infecting prisoners, primarily Chinese prisoners of war and civilians, deliberately with infectious agents, and exposing prisoners to bombs designed to penetrate the skin with infectious particles. There were no known survivors of these experiments; those who did not die from infection were killed to be studied ...

Experiments. Unit 731 and Unit 100 were the two biological warfare research centres set up in spite of the Geneva Protocol of 1925 banning biological and chemical warfare. Led by Lieutenant-General Ishii Shiro, 3,000 Japanese researchers working at Unit 731's headquarters in Harbin infected live human beings with diseases such as the plague ...

ABSTRACT. The Japanese Imperial Army Unit 731's Biological Warfare (BW) research program committed atrocious crimes against humanity in their pursuit of biological weapons de-velopment during the Second World War. Due to an American cover-up, the details behind Unit 731's human experimentation were slow to be revealed.

Japanese Experiment Unit 731: Rare Historical Images. Unit 731 (731部隊), based in the Pingfang district of Harbin and led by the infamous Japanese microbiologist Shiro Ishii, was a covert biological warfare research and development unit of the Imperial Japanese Army that undertook human experimentation during the Second Sino-Japanese War (1937-1945) and World War II.

The story of Unit 731 really began before the Second World War with the person who would eventually lead the unit's activities, Shiro Ishii. Ishii was a medical officer in the Japanese military who specialized in studying infectious diseases. This kind of research was a popular subject for Japanese Army researchers like Ishii, who realized ...

Inside Unit 731 and Japan's Human Experiments in WW2. From 1939 to 1945, the world witnessed the deadliest war in history, as over 30 countries wound together in acrimony, strife, and bloodshed, leading to a war that claimed the lives of more than 100 million people all over the world. History reveals that the war was replete with different ...

The Twisted Story Of Shiro Ishii, The Josef Mengele Of World War 2 Japan. Shiro Ishii ran Unit 731 and performed cruel experiments on prisoners until he was apprehended by the U.S. government — and granted full immunity. A few years after World War I, the Geneva Protocol prohibited the use of chemical and biological weapons during wartime in ...

Unit 731 was the administrative center of the top secret biological warfare project of the Imperial Japanese Army. Located in rural Manchuria, at that time a puppet state of Japan, and known by the codename "the Epidemic Prevention and Water Purification Department", Unit 731's purpose was, in fact, to cause epidemics and contaminated water—for the enemy.

Dr. Futagi's ethically reprehensible human experiments (as in all experiments of Unit 731, all human subjects were eventually killed) had an advantage over ethical experiments addressing the same questions in that they reduced the length of time needed to obtain meaningful results. From a practical perspective, ethical experiments were ...

Three important documents, translated from Japanese to English and each more than 100 pages long, detail Unit 731's clinical observations of the day-by-day spread of various pathogens through the bodies of helpless prisoners whom Japanese doctors subjected to experiments. The U.S. government declassified these key documents, titled "The ...

Select Documents on Japanese War Crimes and Japanese Biological Warfare is a selection of 1,400 documents related to Unit 731 and biological warfare experiments and attacks in World War II. It includes images of about 25 documents in the holdings of the National Archives and will be the starting point for any researcher interested in Japan's ...




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