Chinese Civil War (1945–1949)

After the end of Second Sino-Japanese War, the Chinese Civil War resumed between the Chinese Communists and the Chinese Nationalists. While the Communists were struggling for supremacy in Manchuria, they were supported by the North Korean government with materiel and manpower.^[51] According to Chinese sources, the North Koreans donated 2,000 railway cars worth of material while thousands of Korean "volunteers" served in the Chinese People's Liberation Army (PLA) during the war.^[52] North Korea also provided the Chinese Communists in Manchuria with a safe refuge for non-combatants and communications with the rest of China.^[51]

The North Korean contributions to the Chinese Communist victory were not forgotten after the creation of the People's Republic of China in 1949. As a token of gratitude, between 50,000 to 70,000 Korean veterans that served in the PLA were sent back along with their weapons, and they would later play a significant role in the initial invasion of South Korea.^[51] China promised to support the North Koreans in the event of a war against South Korea.^[53] The Chinese support created a deep division between the Korean Communists, and Kim Il-Sung's authority within the Communist party was challenged by the Chinese faction led by Pak Il-yu, who was later purged by Kim.^[54]

After the formation of the People's Republic of China in 1949, the Chinese government named the Western nations, led by the United States, as the biggest threat to its national security.^[55] Basing this judgment on China's century of humiliation beginning in the early 19th century,^[56] American support for the Nationalists during the Chinese Civil War,^[57] and the ideological struggles between revolutionaries and reactionaries,^[58] the Chinese leadership believed that China would become a critical battleground in the United States' crusade against Communism.^[59] As a countermeasure and to elevate China's standing among the worldwide Communist movements, the Chinese leadership adopted a foreign policy that actively promoted Communist revolutions throughout territories on China's periphery.^[60]