20th century in Harbin

Unit 731 , 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, and maintained multiple branches across mainland China and Southeast Asia.

1932 battle of the Second Sino-Japanese War