Editing Kim Il-sung (section)

=== Communist and guerrilla activities ===
[[File:Kim_Il-sung_in_1927.jpg|thumb|278x278px|Kim Il-sung after joining the military.]]In October 1926, Kim founded the Down-with-Imperialism Union. Kim attended Whasung Military Academy in 1926, but finding the academy's training methods outdated, he quit in 1927. From that time, he attended Yuwen Middle School in China's Jilin province up to 1930, where he rejected the feudal traditions of older-generation Koreans and became interested in Communist ideologies; his formal education ended when the police arrested and jailed him for his subversive activities. At seventeen, Kim had become the youngest member of an underground Marxist organization with fewer than twenty members, led by Hŏ So, who belonged to the South Manchurian Communist Youth Association. The police discovered the group three weeks after it formed in 1929, and jailed Kim for several months.

In 1931, Kim joined the Communist Party of China—the Communist Party of Korea had been founded in 1925, but had been thrown out of the Comintern in the early 1930s for being too nationalist. He joined various anti-Japanese guerrilla groups in northern China. Feelings against the Japanese ran high in Manchuria, but as of May 1930, the Japanese had not yet occupied Manchuria. On 30 May 1930, a spontaneous violent uprising in eastern Manchuria arose in which peasants attacked some local villages in the name of resisting "Japanese aggression." The authorities easily suppressed this unplanned, reckless, and unfocused uprising. Because of the attack, the Japanese began to plan an occupation of Manchuria. In a speech before a meeting of Young Communist League delegates on 20 May 1931 in Yenchi County in Manchuria, Kim warned the delegates against such unplanned uprisings as the 30 May 1930 uprising in eastern Manchuria.

Four months later, on 18 September 1931, the "Mukden Incident" occurred, in which a relatively weak dynamite explosive charge went off near a Japanese railroad in the town of Mukden in Manchuria. Although no damage occurred, the Japanese used the incident as an excuse to send armed forces into Manchuria and to appoint a puppet government. In 1935, Kim became a member of the Northeast Anti-Japanese United Army, a guerrilla group led by the Communist Party of China. Kim was appointed the same year to serve as political commissar for the 3rd detachment of the second division, consisting of around 160 soldiers. Here Kim met the man who would become his mentor as a communist, Wei Zhengmin, Kim's immediate superior officer, who served at the time as chairman of the Political Committee of the Northeast Anti-Japanese United Army. Wei reported directly to Kang Sheng, a high-ranking party member close to Mao Zedong in Yan'an, until Wei's death on 8 March 1941.

In 1935, Kim took the name ''Kim Il-sung'', meaning "Kim become the sun". Kim was appointed commander of the 6th division in 1937, at the age of 24, controlling a few hundred men in a group that came to be known as "Kim Il-sung's division". While commanding this division, he executed a raid on Poch’onbo, on 4 June 1937. Although Kim's division only captured the small Japanese-held town just within the Korean border for a few hours, it was nonetheless considered a military success at this time, when the guerrilla units had experienced difficulty in capturing any enemy territory. This accomplishment would grant Kim some measure of fame among Chinese guerrillas, and North Korean biographies would later exploit it as a great victory for Korea.

For their part, the Japanese regarded Kim as one of the most effective and popular Korean guerrilla leaders. He appeared on Japanese wanted lists as the "Tiger". The Japanese "Maeda Unit" was sent to hunt him in February 1940. Later in 1940, the Japanese kidnapped a woman named Kim Hye-sun, believed to have been Kim Il-sung's first wife. After using her as a hostage to try to convince the Korean guerrillas to surrender, she was killed. Kim was appointed commander of the 2nd operational region for the 1st Army, but by the end of 1940, he was the only 1st Army leader still alive.

Pursued by Japanese troops, Kim and what remained of his army escaped by crossing the Amur River into the Soviet Union. Kim was sent to a camp at Vyatskoye near Khabarovsk, where the Soviets retrained the Korean communist guerrillas. In August 1942, Kim and his army were assigned to a special unit which belongs to the Soviet Red Army. Kim's immediate superior was Zhou Baozhong. Kim became a Major in the Soviet Red Army and served in it until the end of [[World War II]] in 1945.