The Rape of Nanking is only the tip of the spear. Think millions, not tens of thousands. Factories of death such as Unit 731, the Bataan Death March, hell ships, and the originally planned ‘balloon bombs’ were not to carry explosives, but massive quantities of anthrax(hundreds of them made it to the US with explosives, but were ineffective and censored from making the news-hence the Japanese gave up on the idea). Fortunately, try as they might, they were not able to come up with an effective delivery system for biological weapons even after using hundreds of thousands of Chinese citizens to test their ideas. After seeing how dangerous a gram of weaoponized anthrax can be in 2001, its a good thing hundreds of tons of it were never dropped on the US west coast.
http://en.wikipedia.org/wiki/Japanese_war_crimes
