Skirmish between Japanese and Chinese troops at the Luguo Bridge sparks full scale invasion of China by Japanese starting with the Japanese bombing of Nanking (then capital of China) and Shanghai. In December 1937, Japanese ground troops sacked the capital in the Nanking Massacre (Rape of Nanking), an attack marked by massive rape of the women of Nanking. Estimates of death are a subject of controversy and between Japanese and Chinese sources range from 20,000 to 300,000.
Some books that try to assess the treatment of this atrocity are The Nanjing Massacre in History and Historiography edited by Joshua Fogel (a critic of Iris Chang’s book) and The Making of the “Rape of Nanking” History and Memory in Japan, China and the United States by Takashi Yoshida.