Speaking of which, I've been reading a book on 'Unit 731' -- something I knew absolutely nothing about until very recently.
In a nutshell, Unit 731 was a ghastly testing ground for the Japanese Imperial military for designing and learning about the effects of chemical, biological and conventional weapons. They used living prisoners to test all sorts of lethal and sub-lethal devices, like spraying them with plague or tying them up in rows and detonating a bomb to see how lethal its range was. Almost any conceivable military weapon at the time was tested on live subjects.
By some accounts, more than 250,000 were killed in experiments at Unit 731. Some 4,000 Japanese worked at unit 731, but it remained a close secret until the 1980s. After the war it's chief commander, Shirō Ishii, was allowed to retire to a quiet civilian life - he and almost all the other officers involved never went in front of war crime tribunals as the Nazis who ran the concentration/death camps did.
Japanese soldiers also perpetrated the grisly Nanjing Massacre which included evil so bestial that it shocked some of the Nazis who lived there. I was told that soldiers murdered Chinese babies by tossing them up in the air and catching them on bayonets.
Wikipedia“…Nanking should be remembered not only for the number of people slaughtered but for the cruel manner in which many met their deaths.
Chinese men were used for bayonet practice and in decapitation contests.
An estimated 20,000 – 80,000 Chinese women were raped.
Many soldiers went beyond rape to disembowel women, slice off their breasts, and nail them alive to walls.
Fathers were forced to rape their daughters, and sons their mothers, as other family members watched.
Not only did live burials, castration, the carving of organs, and the roasting of people become routine, but more diabolical tortures were practiced, such as hanging people by their tongues on iron hooks or burying people to their waists and watching them get torn apart by German shepherds.
So sickening was the spectacle that even Nazis in the city were horrified, one proclaiming the massacre to be the work of bestial machinery.”