In China at this time, the Nationalist government put pressure on the Communist party with military force. Thus, since 1934 (Showa 9), the Communist party made a big movement (long march), and moved the headquarters to Ienan (Chinese spelling), and during this time Mao Zedong became leader. The next year, the Japanese military from Manchuria and moreover, North China, gathered strength and so,(1) the Communists, in order to oppose the Japanese occupation, called for an end to civil war and in 1937, Chiang Kai-shek was forced to accept.

In North China, the opposing Japanese and Chinese militaries at last encountered each other in the suburbs of Peking (Chinese spelling) on July 1937 (Showa 12). The Japanese military immediately began to expand the battleline to all of North China and also began to fight in Shanghai (Chinese spelling). Thus, the Sino-Japanese War began without a declaration of war. The Japanese military invaded North China, and furthermore, occupied the capital Nanking.

1 Japan, with military power in the background, tried to separate the North China region from the ruling Nationalist government, and reinforced the military more as well as stationed a military garrison in the Peking suburbs ever since the Boxer Rebellion.