 Large scale massacres, rapes, and looting against civilians were committed, most notably the Sook Ching and the Nanjing Massacre, and the use of around 200,000 "comfort women", who were said to be forced to serve as prostitutes for the Japanese military.The Imperial Japanese Army also engaged in the execution and harsh treatment of Allied military personnel and POWs.Biological experiments were conducted by Unit 731 on prisoners of war as well as civilians; this included the use of biological and chemical weapons authorized by Emperor Shōwa himself.