Two of the primary motivating factors for the Japanese in launching the attack were the signing of a non-aggression pact by their German ally with their Soviet enemy, and their defeat by Soviet forces at Nomonhan. A large attack on the Chinese would therefore restore morale. In addition, Germany's invasion of Poland starting on 1 September 1939 gave the Japanese further motivation to crush China's will to fight in order to pave the way for the establishment of Wang Jingwei's () puppet government in Central China ().