Unspeakable crimes committed by WWII Japanese medical personnel experimenting on both civilians and prisoners of war have been well documented.

Read more about:  Dr. Shiro Oshii and Unit 731  and Japan Confronting Gruesome War Atrocity

Unfortunately, unlike modern day Germany that has openly discussed Nazi atrocities, the current Japanese government appears to offer ambivalent views on the matter and even suggest that some aspects in history textbooks warrant revision.