The total death toll of the Nanjing Massacre is a highly contentious subject in Chinese and Japanese historiography. Following the outbreak of the Second Sino-Japanese War, the Japanese Imperial Army marched from Shanghai to the Chinese capital city of Nanking, and though a large number of Chinese POWs and civilians were slaughtered by the Japanese following their entrance into Nanking on December 13, 1937, the precise number remains unknown. Since the late-1960s when the first academic works on the Nanking Massacre were produced, estimating the approximate death toll of the massacre has been a major topic of scholarly debate.