Task: Explanation
Input (English): The American cover-up of Japanese war crimes occurred after the end of World War II, when the occupying US government granted political immunity to military personnel who had engaged in human experimentation and other crimes against humanity, predominantly in mainland China. The pardon of Japanese war criminals, among whom were Unit 731's commanding officers General Shiro Ishii and General Masaji Kitano, was overseen by General of the Army Douglas MacArthur in September 1945. While a series of war tribunals and trials was organized, many of the high-ranking officials and doctors who devised and respectively performed the experiments were pardoned and never brought to justice. As many as 12,000 people, most of them Chinese, died in Unit 731 alone and many more died in other facilities, such as Unit 100 and in field experiments throughout Manchuria. Question: What month did the unit of the Imperial Japanese Army that undertook lethal human experimentation during the Second Sino-Japanese War got pardon? Answer: September
Output (English):  The pardon of Japanese war criminals, among whom were Unit 731s commanding officers General Shiro Ishii and General Masaji Kitano, was overseen by General of the Army Douglas MacArthur in September 1945.