North Korea
Japan tried to suppress Korean traditions and culture and ran the economy primarily for its own benefit. Korean resistance groups known as Dongnipgun (Liberation Army) operated along the Sino-Korean border, fighting guerrilla warfare against Japanese forces. Some of them took part in allied action in China and parts of South East Asia. One of the guerrilla leaders was the communist Kim Il-sung, who later became the first leader of North Korea.
North Korea
During the 1956 August Faction Incident, Kim Il-sung successfully resisted efforts by the Soviet Union and China to depose him in favor of Soviet Koreans or the pro-Chinese Yan'an faction. The last Chinese troops withdrew from the country in October 1958, which is the consensus as the latest date when North Korea became effectively independent. Some scholars believe that the 1956 August incident demonstrated independence. North Korea remained closely aligned with China and the Soviet Union, and the Sino-Soviet split allowed Kim to play the powers off each other. North Korea sought to become a leader of the Non-Aligned Movement, and emphasized the ideology of "Juche" to distinguish it from both the Soviet Union and China.