The following is an introduction in Chinese (not the English translation above):
Unit 731 was an alias for the Epidemic Prevention and Water Supply Headquarters of the old Japanese Army (Kwantung Army). The unit was headed by Shiro Ishii, hence the name "Ishii's Unit".Unit 731 is also a synonym for the clandestine military medical unit of the Japanese Army that invaded China to conduct biological warfare germ warfare research and research related to human experimentation during the War of Resistance Against Japanese Aggression (1937-1945) and the Second World War.
Unit 731 was disguised as a water-purification unit.Unit 731 was based in a cottage area near Harbin in northeastern China, an area that was then part of the puppet regime of Manchukuo. Some researchers believe more than 10,000 Chinese, Korean and allied prisoners of war were killed in Unit 731's experiments, but the number is disputed.
Unit 731 was just one of many war crimes committed by the Imperial Japanese Army during its occupation of Manchuria (from 1931 to 1945, the end of World War II), during which 15 million Chinese, Korean, Filipino, Indonesian, and Burmese civilians, Pacific islanders, and Allied prisoners were killed.