For over 2,000 years China directly or indirectly ruled Vietnam until 1885. The close relationship between the two peoples led to the sinicizing of Vietnamese society. After the end of World War II and the establishment of the People’s Republic of China in 1949, the example of the Chinese revolution persuaded many Vietnamese that they could liberate their country with similar political goals. During the subsequent wars against the French and the Americans, Communist North Vietnam received material as well as political support from China.
Some among the Chinese leadership felt that the Vietnamese had been insufficiently grateful for the aid they had received. Assistance from China and other Communist-bloc countries contributed to Communist North Vietnam’s victory over South Vietnam in 1975. Unified Vietnam became the dominant power in Indochina. In 1979 Vietnamese troops entered Cambodia to oust the Khmer Rouge regime in that country.
China viewed this as an example of Vietnamese expansionism. China also resented Vietnam’s ill treatment of ethnic Chinese residents in the country, and Vietnam’s closeness to the Soviet Union, China’s rival for leadership in the Communist bloc.
Thus the Chinese army (the People’s Liberation Army, or PLA) attacked Vietnam in February 1979. Caught by surprise, the Vietnamese army lost ground, and the PLA successfully achieved the first part of its plan, which was to capture the provincial towns of Cao Bang and Lao Cai and then advance on Lang Son. About 250,000 Chinese troops were deployed, together with militia, the air force, and a naval detachment, to the Spratly Islands in the South China Sea in the event of Soviet intervention to aid Vietnam.
All of the fighting took place in the forested mountainous region that marks the border. Eventually the battle-hardened Vietnamese regrouped against the advance of the PLA. The Soviet Union declined to respond to Vietnamese requests for aid. After a limited advance China declared that it had punished Vietnam and withdrew.
It threatened to return, however, should Vietnam’s actions warrant further punishment. This showed that Communist nations harbored historic resentments against one another: Vietnam’s territorial ambition in Southeast Asia, and China’s attitude toward small states in areas of its historic influence. The conflict put Vietnam firmly in the Soviet camp until the end of the cold war. The fighting continued at a low level along the border.