Unit 731 and the Japanese Imperial Army’s biological warfare program

Unit 731 was the common name of a secret unit of Japan’s Manchuria-based Kwantung Army whose official name was the Epidemic Prevention and Water Supply Department. The leader of the unit was Ishii Shiro (1892-1959), who held the rank of lieutenant general at the end of World War II. The unit epitomized the extensive organization for the development of biological weapons within the Imperial Army, which was referred to, beginning in the late 1930s, as the Ishii Network.