Xu Xiangqian
On October 15, 1936, Guan was promoted to lieutenant general and tasked to block a large Chinese communist force commanded by his former classmate Xu Xiangqian, who had been ordered by the Chinese Communist Party to establish a base in Xinjiang, as part of the communist plan to receive aid from the Soviet Union. General Guan again successfully accomplished his mission and Generalissimo Chiang Kai-shek promoted him to commander of the 52nd corps when the Second Sino-Japanese War broke out the next year. Guan led his unit in successive battles against the Japanese Army, which included the Battle of Taierzhuang, Battle of Wuhan, and Battle of Changsha (1939). Because of his personal bravery, he was nicknamed Guan the Brave and the Iron Fist.