Unit 731

Unit 731
The Unit 731 complex
Location	Pingfan, China
Coordinates	45°36′N 126°38′E / 45.6°N 126.63°E / 45.6; 126.63Coordinates: 45°36′N 126°38′E / 45.6°N 126.63°E / 45.6; 126.63
Date	1935–1945
Attack type	Human experimentation Biological warfare Chemical warfare
Weapons	Biological weapons Chemical weapons Explosives
Deaths	Over 3,000 from inside experiments and tens of thousands from field experiments
Perpetrators	Surgeon General Shirō Ishii Lt. General Masaji Kitano Epidemic Prevention and Water Purification Department

Unit 731 (Japanese: 731部隊, Hepburn: Nana-san-ichi Butai^?) 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 Japan. Unit 731 was based at the Pingfang district of Harbin, the largest city in the Japanese puppet state of Manchukuo (now Northeast China).

It was officially known as the Epidemic Prevention and Water Purification Department of the Kwantung Army (関東軍防疫給水部本部, Kantōgun Bōeki Kyūsuibu Honbu^?). Originally set up under the Kempeitai military police of the Empire of Japan, Unit 731 was taken over and commanded until the end of the war by General Shiro Ishii, an officer in the Kwantung Army. The facility itself was built between 1934 and 1939 and officially adopted the name "Unit 731" in 1941.