盧溝橋事件
After the Xi'an Incident, the Kuomintang led by Chiang Kai-shek and the Communist Party of China led by Mao Zedong formed a United Front against Japan, which was already in control of Manchuria and pushing into North China. The Marco Polo Bridge Incident in July 1937 marked the beginning of the Sino-Japanese War (1937-1945).