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Unit 731 (Japan Human Experiment) – World History – Free PDF Download


  • UNIT 731
  • Detachment 731, The Kamo Detachment,Ishii Unit, Ishii Detachmentor the Ishii Company, was a covert biological and chemical warfare research and development unit of the Imperial Japanese Army that undertook lethal human experimentation during the Second Sino-Japanese War (1937–1945) of World War II.
  • It was responsible for some of the most notorious war crimes carried out by Imperial Japan. Unit 731 was based at 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.


  • In 1932, Surgeon General Shirō Ishii chief medical officer of the Japanese Army was placed in a command of the Army Epidemic Prevention Research Laboratory (AEPRL).
  • Ishii had proposed the creation of a Japanese biological and chemical research unit in 1930
  • It was divided at the same time into the “Ishii Unit” and “Wakamatsu Unit” with a base in Hsinking. From August 1940, the units were known collectively as the “Epidemic Prevention and Water Purification Department of the Kwant or “Unit 731“.

UNIT 731

  • 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.
  • The compilation of all these units comprised Ishii’s network, and at its height in 1939, was composed of more than 10,000 personnel. 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.
  • A special project code-named Maruta used human beings for experiments.


  • Test subjects were gathered from the surrounding population.
  • The test subjects were selected to give a wide crosssection of the population and 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”.
  •  They included infants, men, the elderly, and pregnant women. The members of the unit, approximately 300 researchers, included doctors and bacteriologists


  • Prisoners were injected with diseases, disguised as vaccinations, to study their effects. Prisoners were also repeatedly subject to rape by guards.
  • Thousands of men, women, children, and infants interned at prisoner of war camps were subjected to vivisection, often without anesthesia and usually ending with the death of the victim.
  • Unit 731 were involved in research, development and experimental deployment of epidemic-creating biowarfare weapons in assaults against the Chinese populace (both civilian and military) 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.
  • An attack on Changda in 1941 reportedly led to approximately 10,000 biological casualties and 1700 deaths among ill-prepared Japanese troops, with most cases due to cholera.
  • During biological bomb experiments, researchers dressed in protective suits would examine the dying victims.


  • The resulting cholera, anthrax, and plague were estimated to have killed at least 400,000 Chinese civilians.
  • 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 repeatedly snubbed.
  • 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 Pingfan.


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