World War II
After the Kuomintang (KMT), the governing party of China, unified the country in the 1920s, the Chinese Civil War between it and the Communist Party of China began. In 1931, Japan used the Mukden Incident as a excuse to take Manchuria and set up a puppet state, Manchukuo, and the League of Nations failed to do anything to stop it. The Tanggu Truce, a ceasefire, was signed in 1933. In 1936, the Kuomintang and the communists agreed to stop fighting against each other and to fight Japan instead. In 1937, Japan started the Second Sino-Japanese War to take the rest of China.