National Revolutionary Army soldiers march to the front in 1939. The Second Sino-Japanese War was fought between the Republic of China and the Empire of Japan between 1937 and 1945, following a period of war localized to Manchuria that started in 1931. It is considered part of World War II, and 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 China as the War of Resistance against Japanese Aggression. On 18 September 1931, the Japanese staged the Mukden incident, a false flag event fabricated to justify their invasion of Manchuria and establishment of the puppet state of Manchukuo. This is sometimes marked as the beginning of the war. From 1931 to 1937, China and Japan engaged in skirmishes, including in Shanghai and in Northern China. Chinese Nationalist and Communist forces, r...