In April, the Japanese government released the names of over three thousand members of Unit 731. Unit 731 was a group in the Japanese Imperial Army responsible for some of the worst atrocities committed by the Japanese during World War II. Jack Gray explains.

Shiro Ishii, commander of Unit 731

Shiro Ishii, commander of Unit 731

(1)   Unit 731 is the commonly used name for the Epidemic Prevention and Water Purification Department of the Kwantung Army. It was a secret unit of the Japanese Imperial Army that carried out experiments in biological and chemical warfare using human test subjects. Unit 731 was only one unit of several in the Japanese Imperial Army that carried out medical experiments, but it is the best known. These units were known as the Ishii Network, after Lt. Gen. Ishii Shiro, the commanding officer of Unit 731 who spent his military career researching the development of biological weapons.


(2)   Unit 731 was established in 1936 and operated in the Second Sino-Japanese War and World War II. It was shut down in 1945 after the defeat of Japan. Lt. Gen. Ishii had been carrying out experiments in China in secret since 1933 during the second Sino-Japanese War, although most of these early experiments were much smaller in scale. After 1939, Unit 731’s headquarters were located in Pingfan, near Harbin in China. In its early days most of its members were medical researchers from various Japanese universities, not professional soldiers. There were only eight people in the first group posted to the unit, but it quickly grew in size until there were several thousand members (only a small number were doctors).


(3)   Unit 731 was known for their use of humans as test subjects in horrific experiments studying the effects of plague, frostbite, and other various diseases. While they did carry out several field tests using biological weapons, the use of their weapons was generally less successful than their gruesome experiments. In these, they examined the effects of diseases such as anthrax, cholera, dysentery, plague, smallpox, tetanus, tuberculosis, and typhoid on live human subjects. Researchers infected prisoners with the diseases and then performed vivisections on them while they were still alive to track the progress of the infection. Some experiments studying frostbite involved leaving prisoners outside until their limbs froze and then attempting various methods of reviving the necrotic body parts.


(4)   Many of the members of Unit 731 received immunity from the U.S. government in exchange for the data from their experiments. After the conclusion of the war, Americans began investigating the unit’s experiments and asked for the data, but never used it as evidence to prosecute any members, saying that the information gained from the experiments was too valuable not to take advantage of, since no similar experiments could be carried out in the United States due to moral scruples. In addition, seizing the data prevented the Soviet Union from being able to access it; using the experiments as evidence in a trial would have resulted in making the results public, thereby giving the Soviet Union the information as well. Regardless of the reason, no member of Unit 731 was ever prosecuted by the United States or by Japan.


(5)   The history of Unit 731 has been a contentious issue in Japan, as the government did not disclose any information about the group until recently. Only recently has more information come to light after a request from the public. Many people feel that the lack of any criminal charges against members of Unit 731 is a great injustice, and that the United States should have prosecuted every member. The publication of the names of several thousand members of the unit by the National Archives of Japan was the result of a petition led by Katsuo Nishiyama, a medical professor. The request was first made in 2015, but most of the names on the list were redacted. Only in January of 2018 did the government agree to release the rest of the names. Katsuo hopes that the release of the names will lead to greater awareness of the unit’s history and a new commitment never to repeat the crimes of the past.


To summarize, Unit 731 was a group in the Japanese Imperial Army during World War II that was responsible for war crimes involving experimentation on live human beings, but escaped prosecution. Only recently have the names of the members of the Unit come to light. Hopefully with this new information there will be new commitments to avoid further atrocities and remember those who suffered.


Jack Gray is from Pacific Atrocities Education,


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AuthorGeorge Levrier-Jones