On December 9, after unsuccessfully demanding the defending Chinese troops in Nanjing to surrender, the Japanese troops launched a massive assault on the city. On the December 12, the Chinese troops decided to retreat to the other side of Yangtze River. On December 13, the 6th and the 116th Divisions of the Japanese Army first entered the city. At the same time, the 9th Division entered Guanghua Gate, and the 16th Division entered Zhongshan and Taiping Gates. In the afternoon, two Japanese Navy fleets arrived on both sides of the Yangtze River. On the same day, Nanjing fell to the Japanese. In the following 6 weeks the Japanese troops committed the infamous Nanking Massacre.
See also: Sino-Japanese War (1937-1945)