who did the nationalists and communists in china form an alliance against
Second United Front The Second United Front was the alliance between the Chinese Nationalist Party (Kuomintang, or KMT) and Communist Party of China (CPC) to resist the Japanese invasion during the Second Sino-Japanese War, which suspended the Chinese Civil War from 1937 to 1941.
Second Sino-Japanese War Initially the Japanese scored major victories, capturing both Shanghai and the Chinese capital of Nanking in 1937. After failing to stop the Japanese in the Battle of Wuhan, the Chinese central government was relocated to Chongqing (Chungking) in the Chinese interior. By 1939, after Chinese victories in Changsha and Guangxi, and with Japan's lines of communications stretched deep into the Chinese interior, the war reached a stalemate. The Japanese were also unable to defeat the Chinese communist forces in Shaanxi, which waged a campaign of sabotage and guerrilla warfare against the invaders. While Japan ruled the large cities, they lacked sufficient manpower to control China's vast countryside. During this time, Chinese communist forces launched a counter offensive in Central China while Chinese nationalist forces launched a large scale winter offensive.