Since most Japanese military records on the killings were kept secret or destroyed shortly after the surrender of Japan in 1945, historians have been unable to accurately estimate the death toll of the massacre. In 1946, the International Military Tribunal for the Far East in Tokyo estimated that over 200,000 Chinese were killed in the massacre. China's official estimate is more than 300,000 dead based on the evaluation of the Nanjing War Crimes Tribunal in 1947. The death toll has been contested by scholars since the 1980s.