The Battle of Nanking was fought in early December 1937 during the Second Sino-Japanese War between the Chinese National Revolutionary Army and the Imperial Japanese Army for control of Nanjing (Nanking), the capital of the Republic of China.

The Second Sino-Japanese War was the war fought between the Republic of China and the Empire of Japan from 1937 to 1945 as part of World War II. It is often regarded as the beginning of World War II in Asia. It was the largest Asian war in the 20th century and has been described as "the Asian Holocaust", in reference to the scale of Japanese war crimes against Chinese civilians. It is known in Japan as the Second China–Japan War, and in China as the Chinese War of Resistance against Japanese Aggression.