Unit 731

Unit 731 (Japanese: 731部隊, Hepburn: Nana-san-ichi Butai), officially known as the Manchu Detachment 731 and also referred to as the Kamo Detachment and the Ishii Unit, was a secret research facility operated by the Imperial Japanese Army between 1933 and 1945. It was located in the Pingfang district of Harbin, in the Japanese puppet state of Manchukuo (now part of Northeast China), and maintained multiple branches across mainland China and Southeast Asia. Unit 731 was responsible for large-scale biological and chemical warfare research, as well as lethal human experimentation. The facility was led by General Shirō Ishii and received strong support from the Japanese military. Its activities included infecting prisoners with deadly diseases, conducting vivisection, performing organ harvesting, testing hypobaric chambers, amputating limbs, and exposing victims to chemical agents and explosives. Prisoners—often referred to as "logs" by the staff—were mainly Chinese civilians, but also included Russians, Koreans, and others, including children and pregnant women. No documented survivors are known. An estimated 14,000 people were killed inside the facility itself. In addition, biological weapons developed by Unit 731 caused the deaths of between 200,000 and 500,000 people in Chinese cities and villages, through deliberate contamination of water supplies, food, and agricultural land. After the war, twelve Unit 731 members were tried by the USSR in the 1949 Khabarovsk war crimes trials and sentenced to prison. However, many key figures, including Ishii, were granted immunity by the United States in exchange for their research data. The Truman administration concealed the unit's crimes and paid stipends to former personnel. On 28 August 2002, the Tokyo District Court formally acknowledged that Japan had conducted biological warfare in China and held the state responsible for related deaths.