The rapid ascent of Lieutenant General Yu Kyong Su to the command of III Corps would indicate that promotion was sometimes due to political influence. A graduate of a Red Army tank school in 1938 at the age of 33, Yu served throughout World War II as a company grade officer in a Soviet tank unit. After his return to Korea, he married Kim Il Sung’s sister and shot up from the command of an NK tank regiment in 1948 to the rank of corps commander late in 1950. During the first few weeks of the invasion, he was awarded the highest NKPA decoration, the “Hero of the Korean Democratic People’s Republic,” with a concurrent award, the “Order of the National Flag, 1st Class.”
On the other hand, the career of former Lieutenant General Kim Mu Chong, ex-commander of II Corps and ex-chief of artillery, was blasted by the opposition of Kim Il Sung and Nam Il. A CCF veteran, Mu had served under Mao Tse-tung on the “Long March” as one of 30 Koreans to survive the ordeal. He commanded a Chinese artillery brigade and was rated the best CCF artilleryman. In 1945 he came back to Korea and conducted a speaking tour stressing the desirability of cooperating with Red China and omitting any reference to the Soviet Union. This lapse explains his failure in North Korean politics, but in deference to his high military reputation he was given command of II Corps in June 1950. The poor showing made by his units on the central front was ascribed by Mu to the fact that Kim Il Sung picked him for missions which could not succeed. Although he did not lack for support in the army, Mu was relieved of his command and other positions in the late summer of 1950. Expulsion from the North Korean Labor Party followed after Kim Il Sung denounced him in a speech for disobedience of orders.
Mu’s downfall was only one chapter in the bitter struggle for power waged by two opposing tactical schools in the North Korean army from 1948 to 1950. Veterans of CCF campaigns against the Japanese and Chinese Nationalists upheld a system of large-scale guerrilla warfare refined into a military science. Approach marches under cover of darkness, infiltrations, probing night attacks--these were the basic tactics employed by Mao Tse Tung’s forces for the conquest of China. Although mobility was the keynote, a rigid tactical system allowed little latitude of decision to officers below the regimental level. School solutions were provided for every military problem that could be foreseen, and many of the North Korean officers had graduated from the CCF military academy at Yenan.