Japan History Lab

Unit 731: The Side of the Scientist

When thinking about medical experimentation during World War II (WWII), one’s mind often turns to Josef Mengele’s experiments at Auschwitz. Josef Mengele and his experiments are infamous and their brutality is known around the world, yet Unit 731 is rarely talked about. Unit 731 was a program created by the Japanese Government, in which thousands of lethal biological and chemical experiments were carried out on Japan’s prisoners of war during WWII. Most people have never heard about Unit 731 nor are they aware that a unit of the Japanese Army in WWII was doing biological and chemical experimentation. Many of the documents from Unit 731 were intentionally destroyed, the victims very rarely survived and the majority of the staff and leaders died without giving a confession, which makes it difficult to gather information into the daily life within the walls of Unit 731. This essay will address Unit 731 by looking at some of the atrocities that were committed, highlighting the leader of the unit, as well as commenting upon what is being done at the location of Unit 731 now.

Unit 731 is responsible for the suffering and death of thousands of individuals through barbaric and appalling biological and chemical experiments. The Kempeitai –the Japanese Military Police Corps – provided most of these victims and they were “Manchurians, Chinese, Russians, Koreans, Europeans and Americans” (290).1 The treatment of these individuals did not differ between the ethnicities nor did the way in which they were acquired. They were subjected to many different bacteria including “cholera, typhoid, dysentery, anthrax and bubonic plague”(290).1 Quite often, vivisections were performed on patients with no anesthetic, using only restraints to help hold the individual in place. Many women were raped until they were pregnant and then vivisected in order to see what changes the female body experienced whilst pregnant. Other experiments included “tying victims to stakes and bombarding them with shrapnel laced with gangrene; inserting them in pressure chambers to see how much their bodies could take before their eyes popped; and exposing them, periodically drenched in water, to subzero weather to determine their susceptibility to frostbite ”(290).1

Very rarely did an individual survive these experiments and if they did, they would undergo more experiments until their body finally gave out. Victims very rarely made it out of Unit 731 alive.

During WWII Unit 731 was covered up, as it was officially known as the ‘Epidemic Prevention and Water Purification Department of the Kwantung Army’. The Unit was set up in Pingfang China, the largest city in the Japanese puppet state of Manchukuo, and was commanded until the end of the war by Ishii Shirō. It was created after the biological testing center that General Ishii Shirō had been working at in Manchuria blew up in 1934. It became possible for Unit 731 to exist in the 1930’s rather than the 1920’s or earlier because it became common knowledge that a war was going to breakout and the Japanese government felt that preparations were necessary. Japan wanted to be prepared for a war and they wanted to continue to conquer countries therefore, they felt that biological and chemical warfare testing was necessary. Biological and chemical warfare were seen as the weapons that would win the coming wars and Japan wanted to continue their expansion throughout Asia. The unit was supported by the Japanese army as they were interested in biological warfare, however its experiments were kept hidden until the end of the war when they were discovered by the US Army. Following the war, most of the documents were destroyed by the Japanese government in order to hide what had been happening and there were several attempts to destroy the facilities as well. Unit 731 was located “near Pingfan railway station, 20 kilometers from the city of Harbin in northeastern China”(97).2 Although it was created in 1936, by “early 1939 a large-scale military camp with many laboratories and service buildings had been constructed ” in order to facilitate the thousands of experiments that would take place in the coming years (97).2 Unit 731 was made up of eight divisions carefully plotted and planned out: Human experimentation in division 1, research for biological weapons was completed in division 2, shells filled with biological agents were made in division 3, division 4 was reserved for miscellaneous tasks, division 5 was used to train the personnel and divisions 6 thru 8 were used for equipment and administrative purposes (97).2 All of these divisions were housed in the roughly 150 buildings which housed the well over 3,000 victims and covered the 6 square kilometers in which the Unit 731 complex was located.3

Ishii Shiro’s hand drawn map of Unit 731

Ishii Shiro’s hand drawn map of Unit 731 3.

Ishii Shirō was the man in charge of Unit 731 until the end of WWII. He graduated from the Imperial University in Kyoto in 1920 and joined the Imperial Army (167).4 He had always been interested in infectious diseases and began to experiment with bacteria as a possible weapon of war. In 1932, he was “placed in command of the Epidemic Prevention Research Laboratory in Tokyo which…had the primary task of creating chemical and biological weapons ” (167).4 Several years later, he moved the location of his experiments to Manchuria where Unit 731 experimentation took place. Ishii Shirō trained those who worked under him to not see the victims as people. He taught them to “[refer] to their victims as maruta, a Japanese term for ‘logs of wood’ or ‘lumber’ ”(27).2 By teaching his workers and colleagues to dehumanize the victims, Ishii Shirō made it easier for them to unleash as much brutality as possible upon the captives and prisoners. Ishii Shirō was the one responsible for the command unit and the decisions of Unit 731.

Following the war, many workers from Unit 731 were imprisoned and tortured until they confessed to what had been happening within the walls of this place of experimentation and brutality. Yuasa Ken was a doctor at Unit 731 who has commented on his experience there. In his confession, he describes his first day at Unit 731 and what he encountered when he first arrived. On his first day, he walked straight into an operating room where there were two men awaiting surgery. The operations took several hours, during which the men were sliced open and the doctors were free to explore and dissect the individual however they pleased. These men were not sedated and were expected to eventually bleed out on the table to which they were strapped. Following the surgery, one of the men who had been sliced open began to gasp – he was still alive.5 They then attempted to kill him by “[injecting] air into his heart with a syringe… [strangling] him with string…finally…[giving] him a shot of anesthesia…afterwards [they] threw him into the hole ” where all bodies were deposited.5 Yuasa Ken was being trained at Unit 731 so that he might serve as an army doctor for the Japanese Army and help the men on the front line. He operated at Unit 731 for several years before eventually working as an Army Doctor and training others. He was imprisoned in China for his role at Unit 731 and was released in 1956 when he then returned to Japan.

Following the surrender of Japan in 1945, American army leaders arrived in Japan and began questioning individuals regarding the biological testing. Although the American troops did not agree with the testing that had taken place during WWII, they agreed to make a deal with the leaders and staff of Unit 731. Following the war, the “United States granted immunity from prosecution to the members of this unit in exchange for the information [from] the experiments”(68).4 The United States received a lot of negative backlash from around the world for the decisions made pertaining to the members of Unit 731. The United States agreement made it so that “the Japanese scientists [received] 250,000 yen…in exchange for their data, but [also] immunity from prosecution of war crimes”(57).2 This agreement was “granted to all those associated with the program” not just the doctors who performed the experiments (57).2 When the United States made the deal, they had “full knowledge that the data collected [was] from human subjects, almost all of whom were killed in the experiments” some of whom were United States prisoners of war (57).2

Ishii Shirō managed to “[negotiate] immunity from war crimes prosecution” following the war due to the agreement that had been made with the United States (167).4 There were close to 3000 staff working at Unit 731 yet only “nine of the accused were charged with crimes committed while they were serving with…Unit 731”(97).2 Since the vast majority of the staff who worked at Unit 731 were able to simply walk away with no repercussions, they were able to have “successful academic and business careers after the war” (338).4 Despite these individuals having tortured and murdered thousands of people, they were still allowed to return to a normal life at the end of the war – many of them working as doctors once more.

Following the Tokyo War Crimes trial, during which many of the accused walked free, the public became interested in Unit 731. Interest in the experiments that had taken place began to rise in the 1990s, as well as in the individuals who were involved. Ishii Shirō was shunned from society following the war and he was “unable to find consistent employment and died…in 1959” (167).4 The public was appalled that these atrocities were allowed to take place and that they were condoned by the Japanese Government and seemingly the United States Armed Forces. There are records showing “requests from a Japanese pharmaceutical company [asking] for brain-cortex tissue…[and later] a second request came from the company asking for ten bottles [of brain-cortex tissue].”5 More and more companies were revealed to have been involved with Unit 731 and their findings and the public soon began to feel that “everybody was involved” and that they had been betrayed by their government.5

Today, “23 sites are listed as the key sites for protection to testify to the crimes” and they are open to the public.6 They have been preserved by the Japanese people, and now tours of the sites are offered. The tours are used to give a voice to those who died so that they may never be forgotten. Just outside the site of Unit 731, is a plaque outlining a brief history of the atrocities that occurred here and refers to it as “the den of cannibals.”6 Even though the public is interested in learning more about Unit 731, “official denial of war crimes and denial of official compensation for victims, supported by neo-nationalist individuals and non-governmental groups of ‘deniers,’ remain in place” (29).2 The Japanese Government is still not willing to admit to the atrocities that took place at Unit 731 let alone delve into details pertaining to Unit 731. There have been many “heroic efforts by many individuals and organizations to face history squarely” yet it seems to have had little to no impact on the Japanese government (29).2

The plaque outside the site of Unit 731

The plaque outside the site of Unit 731 6.

Although there are people fighting for Unit 731 to be recognized by the Japanese Government, asking that there be an admission of guilt and a formal apology, this seems to have fallen on deaf ears by those able to enact such a response. For the horrors of Unit 731 to come into the full light of public scrutiny, there needs to be a full and complete process of the gathering of data and full description of the complete historical picture. Public protest is simply not enough. It is important that historians and teachers not focus solely on the European aspects of WWII, but also on the Asian front. The victims of Unit 731 must never be forgotten, nor should the staff be permitted to have their names slip away into oblivion. Unit 731 and its atrocities need to be remembered and discussed in the same way as the Josef Mengele experiments.