In 1933, Guan received orders from the nationalist government to help General
Song Zheyuan defend North China against the
Imperial Japanese Army led by Field Marshal
Nobuyoshi Mutō in the
Defense of the Great Wall. He personally led an infantry charge against a Japanese position and was severely wounded in the action, his deputy commander
Du Yuming took over command of the division. The nationalist government awarded him the
Order of Blue Sky and White Sun after the conclusion of the battle. General Guan's unit stayed in
Beiping after this clash as part of the garrison and was post in
Luoyang in 1935. In 1936, he led his unit into
Shanxi province to help the local warlord
Yan Xishan to drive away the communist troops commanded by his former classmate
Lin Biao and was successful in his mission. 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. Guan defeated the communists in this campaign and 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. In 1938, General Guan was promoted to command the 33rd army, and was promoted to the position of commander-in-chief of 15th army group, becoming the first graduate of the
Whampoa Military Academy to command an army group. In 1940, Guan led his unit into
Yunnan, and was put in charge of defending the border between China and
French Indochina. However, Guan's relation with General
Chen Cheng suffered another setback when he decided to remove Chen Cheng's favorite commander General
Huang Wei as commander of the 54th corps because of Huang's alleged corruption. In 1944, General Guan received another promotion as deputy commander-in-chief of the 1st Area Army. ==Chinese Civil War==