731 is also the unit number of a bio-chemical research station stationed in Harbin, China.
This Unit 731 was established by the Japanese forces that occupied Chinese Manchuria during World War II. It was the site of many atrocities as the Japanese conducted numerous "experiments" on the hapless prisoners of war shipped from all over their Pacific Emipre.
The Japanese experimented on the airborne release of smallpox over the neighboring towns, studied the spread of deadly diseases by spreading germ-infected candies and treats to the children of Harbin. When Unit 731 was being built, it was to be planned the most technologically advanced medical research center and therefore sported pressure chambersto experiment on biological responces to pressure change, gigantic freezers in which humans could be frozen to study effects of frostbite, and large "bomb chambers" where live humans could be literally blown apart to study the effects of shapenel on a human body. These Japanese experiments can pale those of the infamous Nazi Doctors that have been so widely publicized.
Yet, most citizens of America dont know about the atrocities of Harbin, probably because the U.S. government signed a clandestine pact with the Japanese and traded the study documents in return for the doctors' exemption from war crimes. Even now, the Japanese government in an attempt to save face, does not acknowledge that the atrocities at Harbin ever took place. Although Unit 731 is forever stained into the Asian mind, it has yet to recieve worldwide recognition.