 The book discussed the research of historian Sun <unk> of the Jiangsu Academy of Social Sciences . In his 1990 paper , The Nanking Massacre and the Nanking Population , Sun estimated the total number of people killed at 377 @,@ 400 . Using Chinese burial records , he calculated that the number of dead exceeded the figure of 227 @,@ 400 . He then added estimates totaling 150 @,@ 000 given by Japanese Imperial Army Major Ohta Hisao in a confessional report about the Japanese army 's disposal efforts of dead bodies , arriving at the sum of 377 @,@ 400 dead . 
