Unit 731 was a Japanese wartime research facility responsible for experimenting on people: prisoners-of-war and local Chinese (link). Gruesome experiments on living humans and large scale germ-warfare trials were carried-out by medical personnel under control of the Japanese occupying military authority.
We don't know as much as we should about the horrors of Unit 731, Surgeon General Shirō Ishii, and superiors in Tokyo (731部隊と石井四郎) because of huge postwar cover-up when the blood-soaked data was bartered to the American military. (Some background here - link)
Now Japan would have us believe Unit 731 victims "volunteered" for sacrifice - without anesthesia or ceremony. Sure...
