The Chinese Civil War, fought between the Nationalists (Kuomintang or KMT) and the Communists (CCP), was interrupted during World War II when China faced an invasion by Japan. The conflict between the KMT and CCP was paused to form a united front against the Japanese invasion, which began in full-scale with the Marco Polo Bridge Incident in 1937, marking the start of the Second Sino-Japanese War.