In October 1945, one month after the surrender of the Japanese, Wang was promoted to lead one of the seven columns of the Northwest Field Army, under the command of Peng Dehuai. Wang fought against the Kuomintang until most of Chiang Kai-shek's forces were withdrawn to Taiwan in September 1949. In October Wang's forces were directed by Peng to occupy Xinjiang. Most defenders surrendered peacefully to Wang and were incorporated into the PLA.