The August faction incident, officially called the "Second Arduous March", was an attempted removal of Kim Il Sung, the chairman of the Workers' Party of Korea and the premier of North Korea, from power by leading North Korean figures from the Soviet faction and the Yan'an faction, with support from China and the Soviet Union, at the second plenary session of the 3rd Central Committee of the Workers' Party of Korea (WPK) in 1956. The attempt to remove Kim failed and the participants were arrested and later executed. Through this political struggle, Kim quashed all opposition to him within the party leadership.

The leaders of the coup included the Vice Premier of the Cabinet Ch'oe Ch'angik, the Chairman of the Standing Committee of the Supreme People's Assembly Kim Tu-bong, the Minister of Construction Kim Sung-hwa, the Minister of Commerce Yun Gong-chin, and the Chairman of the General Federation of Trade Unions Suh Hwi, all of whom were members of the reformist faction within the WPK. They opposed Kim Il Sung's cult of personality and believed that his economic policies and policies caused serious problems. The plot was dismantled in just half a day and the plotters were purged. Afterwards, the plotters convinced China and the Soviet Union to send a joint delegation headed by Peng Dehuai and Anastas Mikoyan to force Kim to revert his purge. Kim temporarily relented, convincing China and the Soviet Union to not remove him from power, but he resumed his purges soon afterwards,

Regarded by historians as one of the most far-reaching events in North Korea, Kim Il Sung's power was not only not challenged, but was gradually consolidated due to the plot. It also indirectly laid the foundation for the Kim family's long-term rule over North Korea and affected the country's relations with China and the Soviet Union.

Since the founding of North Korea in 1948, the ruling party of the country has been the Workers' Party of Korea. However, since the party was formed by the merger of many different factions of communist and non-communist parties, there emerged different factions in the WPK. Among them included the Soviet faction of those hailing from the Soviet Union, the Yan'an faction which had close ties with the Chinese Communist Party, the domestic faction composed of former members of the Workers' Party of South Korea, and the guerrilla faction whose members fought against the colonial government during the Japanese rule of Korea. The guerrilla faction and the Yan'an faction were considered to have made the greatest contributions during the resistance against Japan. With the support of the Soviet Union, Kim Il Sung, the leader of the guerrilla faction, became North Korea's supreme leader. The Yan'an faction secured 6 out of 13 seats in the Politburo of the Workers' Party of Korea. These two factions thus became the most influential factions in the party at that time.

In 1948, the Soviet Red Army withdrew from the Korean Peninsula, meaning that Kim Il Sung lost Soviet military support. To prevent other factions from taking the opportunity to expand their power, he purged the leaders of various factions during the Korean War, which he launched in 1950. In December 1950, he first dismissed Mu Chong, the leader of the Yan'an faction and vice minister of the National Defense Department and commander of the artillery of the Korean People's Army, for failing to defend Pyongyang. In 1951, he dismissed Ho Ka-i, the leader of the Soviet faction, from all his posts on charges of failing to repair the reservoir and obstructing the expansion of the party.

During this time, there was increasing conflict between Kim Il Sung and Pak Hon-yong, the leader of the domestic faction. Pak was originally a core figure of the Communist Party of Korea and was highly respected by the Soviet Union. He later joined the Workers' Party and was highly regarded within the party. On the other hand, his position on many policies was contrary to that of Kim Il Sung. The two had different views on how to launch an offensive against South Korea and whether to negotiate peace during the war. In November 1952, Pak Hon-yong delivered a speech commemorating the 35th anniversary of the October Revolution. When mentioning the Korean independence movement, he repeatedly emphasized the leading position of the Korean Communist Party and did not mention Kim Il Sung's name. Considering the lack of foreign support for the domestic faction and their dissatisfaction with Pak, Kim Il Sung arrested him in 1953 on the grounds that he was a spy for the United States. In July 1953, the Korean War ended, and Kim Il Sung continued his purge. Ten people, including Yi Sung-yop and Kwon Oh-jik, were executed on the same day for espionage, leading the domestic faction's power to plummet.

Afterwards, Kim Il Sung turned his attention to Pak Il-u, a representative of the Yan'an faction who held military power. During the Korean War, Pak was the Minister of Internal Affairs and Deputy Political Commissar of the Joint Command, and was the liaison between the North Korean government and Beijing. Towards the end of the war, Kim Il Sung informed Beijing that Pak would be recalled and replaced by his confidant Choe Yong-gon. However, although Pak had been relieved of his post of liaison with Beijing, he still maintained contact with the Chinese government, which displeased Kim Il Sung. At the plenary session of the Central Committee of the Workers' Party of Korea held in April 1955, Kim Il Sung criticized Pak Il-u by name for "posing as a representative from China", forming cliques and attempting to split the party, and placed him under house arrest. In December 1956, he was expelled from the Central Committee and his party membership was revoked.

The Soviet faction then became the target of the attack. According to official Soviet archives, Kim Il Sung had no hostility toward the Soviet faction after eliminating Ho Ka-i. However, with Pak Chang-ok's large-scale promotion of Soviet faction cadres in 1955, he had objections to Kim's handling of Ho Ka-i, which increased Kim Il Sung's suspicion. In order to attack Pak Chang-ok, Kim Il Sung misled Pak's confidant, Park Yong-bin, the Minister of Propaganda of the WPK Central Committee, to explain the "historical role of the masses" when publishing periodicals. Coincidentally, Song Dal-beom, the editor of the political propaganda magazine New Joseon, refused to publish the novel by Han Sorya, a writer who was deeply loved by Kim Il Sung. In this way, Kim Il Sung found more reasons to criticize Park. At the subsequent Central Committee plenary session, Kim dismissed Park Yong-bin from his post for his erroneous tendencies in literary work and his attack on proletarian literature. As for Pak Chang-ok, considering his active role in the previous struggle against Pak Hon-yong, he was only expelled from the Political Committee, but retained his position as Vice Prime Minister. Nevertheless, the main Soviet faction cadres had all been expelled from the core of power.