The so-called rape of the Chinese city of Nanking occurred during World War 2 and was committed by soldiers of the Japanese Army. Over a period of six weeks, nearly 400,000 civilians were murdered and an estimated 20,000 women were raped by the Japanese occupying army. While this was not the same level as the German Holocaust, it was still a very serious travesty and is a tale often absent from history books.
The Japanese weren't very discriminative in the women they raped: girls as young as seven and women approaching one hundred were brutally raped, sometimes by multiple soldiers at once and on repeated occasions. In some cases, the Japanese soldiers seized the women and held them prisoner in order to continue raping them whenever they wanted.
These rapes weren't committed in privacy, instead being performed in public, where the families of the women were forced to watch or even participate. The Japanese officials ordered the soldiers to murder the women when the soldiers were done with them, a practice most performed by cutting off the women's breasts or disemboweling them. Even the most senior of officers participated in these atrocities.
Horror stories of the massacre abound, including one that is particularly gruesome. After continuously gang raping a pregnant Chinese woman, the soldiers murdered her and cut out her fetus. The fetus was presented to their commander on a bayonet, evoking no small amount of laughter from the officer.
The Japanese soldiers commonly took trophies from their deeds. Such trophies could be valuables from the homes of the Chinese or body parts. A popular practice was the collection of heads or hands from civilian corpses.
Many have accused the writers of Japanese textbooks of whitewashing this and other atrocities that occurred during World War 2. Despite numerous apologies by the Japanese government to the people of China, many Chinese still harbor an anti-Japanese sentiment, which is expressed by large protests and occasional attacks on Japanese citizens visiting China.