Unit 731 was based at the Pingfang district of Harbin, the largest city in the Japanese puppet state of Manchukuo
(now Northeast China).

More than 10,000 people—from which around 600 every year were provided by the Kempeitai—
were subjects of the experimentation conducted by Unit 731.

More than 95% of the victims who died in the camp based in Pingfang
were Chinese and Korean, including both civilian and military. The remaining 5% were South East Asians
and Pacific Islanders
, at the time colonies of the Empire of Japan,
and a small number of the prisoners of war from the Allies of World War II.

According to the 2002 International Symposium on the Crimes of Bacteriological Warfare,
the number of people killed by the Imperial Japanese Army germ warfare and human experiments is around
580,000.
According to other sources, the use of biological weapons researched in Unit 731's
bioweapons and chemical weapons programs resulted in possibly as many
as 200,000 deaths of military personnel and civilians in China.

Unit 731 was the headquarters of many subsidiary units
used by the Japanese to research biological warfare; other units included Unit 516, Unit 543, Unit 773,
Unit 100 Unit Ei 1644 , Unit 1855 , Unit 8604 ,
Unit 200 and Unit 9420.