Chinese forces of the People’s Liberation Army (PLA) attacked Lang Son, taking the city on March 4, 1979 after bitter house-to-house fighting. The following day, the Chinese government, declaring that it had sufficiently punished Vietnam, ordered its forces to withdraw from Vietnam. On their withdrawal, the PLA carried out a scorched-earth campaign, destroying buildings, properties, and farmlands, before crossing into China on March 16, 1979. But the PLA did not cede the 60 km2 strip of disputed border territory which it had captured during the invasion. The continued hold by the Chinese of this territory would become a source of dispute in the ensuing decade.
The Sino-Vietnamese War was over. No official casualty figures exist, as China and Vietnam have not released their battlefield human losses incurred during the war. But perhaps the PLA suffered some 60,000 troops killed or wounded, with Vietnamese forces suffering a nearly equivalent number of casualties.
(Taken from Sino-Vietnamese War – Wars of the 20th Century – Twenty Wars in Asia)
Background In late December 1978, Vietnam invaded Cambodia, and within two weeks, its forces toppled the Khmer Rouge government, and set up a new Cambodian government that was allied with itself (previous article). The Khmer Rouge had been an ally of China, and as a result, Chinese-Vietnamese relations deteriorated. In fact, relations between China and Vietnam had been declining in the years prior to the invasion.
During the Vietnam War (separate article), North Vietnam received vital military and economic support from China, and also from the Soviet Union. But as Chinese-Soviet relations had been declining since the early 1960s (with both countries nearly going to war in 1969), North Vietnam was forced to maintain a delicate balance in its relations between its two patrons in order to continue receiving badly needed weapons and funds. But after the communist victory in April 1975, the reunified Vietnam had a gradual falling out with China over two issues: the persecution of ethnic Chinese in Vietnam, and a disputed border.
Following the Vietnam War, the Vietnamese central government in Hanoi launched a campaign to break down the free-market economic system in the former South Vietnam to bring it in line with the country’s centrally planned socialist economy. Ethnic Chinese in Vietnam (called Hoa), who controlled the South’s economy, were subject to severe economic measures. Many Hoa were forced to close down their businesses, and their assets and properties were seized by the government. Vietnamese citizenship to the Hoa was also voided. The government also forced tens of thousands of Hoa into so-called “New Economic Zones”, which were located in remote mountainous regions. There, they worked as peasant farmers under harsh conditions. The Hoa also were suspected by the government of plotting or carrying out subversive activities in the North.
As a result of these repressions, hundreds of thousands of Hoa (as well as other persecuted ethnic minority groups) fled the country. The Hoa who lived in the North crossed overland into China, while those in the South went on perilous journeys by sea using only small boats across the South China Sea for Southeast Asian countries. Vietnam also initially refused to allow Chinese ships that were sent by the Beijing government to repatriate the Hoa back to China. The Hanoi government also denied that the persecution of Hoa was taking place. Then when the Hanoi government allowed the Hoa to leave the country, it imposed exorbitant fees before granting exit visas. Furthermore, North Vietnamese troops in the northern Vietnamese frontier regions forced ethnic Chinese who lived there to relocate to the Chinese side of the China-Vietnam border.
Vietnam and China also had a number of long-standing territorial disputes, including over a piece of land with an area of 60 km2, but primarily in the Gulf of Tonkin, and in the Spratly and Paracel Islands in the South China Sea. The dispute over the Spratly and Paracel Islands became even more pronounced after it was speculated that the surrounding waters potentially contained large quantities of petroleum resources.
The Vietnamese also generally distrusted the Chinese for historical reasons. The ancient Chinese emperors had long viewed Vietnam as an integral part of China, and brought the Vietnamese under direct Chinese rule for over a millennium (111 B.C.–938 A.D.). Then during the Vietnam War, the Vietnamese accepted Chinese military support with some skepticism, and later claimed that China provided aid in order to bring Vietnam under the Chinese sphere of influence. Furthermore, China’s improving relations with the United States following U.S. President Richard Nixon’s visit to Beijing in 1972 also was viewed by North Vietnam as a betrayal to its reunification struggle during the Vietnam War. In May 1978, with Cambodian-Vietnamese relations almost at the breaking point, China cut back on economic aid to Vietnam; within two months, it was ended completely. Also in 1978, China closed off its side of the Chinese-Vietnamese land border.
Meanwhile, just as its ties with China were breaking down, Vietnam was strengthening its relations with the Soviet Union. In 1975, the Soviets provided large financial assistance to Vietnam’s post-war reconstruction and five-year development program. Two events in 1978 brought Vietnam firmly under the Soviet sphere of influence: in June, Vietnam became a member of the Soviet-led Council for Mutual Economic Assistance (Comecon) and in November, Vietnam and the Soviet Union signed the “Treaty of Friendship and Cooperation”, a mutual defense pact that stipulated Soviet military and economic support to Vietnam in exchange for the Vietnamese allowing the Soviets to use air and naval facilities in Vietnam. The treaty also formalized the Soviet and Chinese domains in Indochina, with Vietnam aligned with the Soviet Union, and Cambodia aligned with China.
China now saw itself surrounded by the Soviet Union to the north and Vietnam to the south. But Vietnam also saw itself threatened by hostile forces in the north (China) and southwest (Cambodia). Vietnam then made its move in late December 1978, when it invaded Cambodia and conquered the country in a lightning offensive. Chinese authorities were infuriated, as their ally, the Khmer Rouge regime, had been toppled by the Vietnamese invasion. Since one year earlier (1978), tensions between China and Vietnam had been rising, causing many incidents of armed clashes and cross-border raids. In January 1979, the Hanoi government accused China of causing over 200 violations of Vietnamese territory.
By February 1979, 30 divisions of the People’s Liberation Army, or PLA (China’s armed forces) were massed along the border. On February 15, 1979, China announced its plan to attack Vietnam. Also on that day, China’s 1950 “Treaty of Friendship, Alliance, and Mutual Assistance” with the Soviet Union ended, thus freeing China from its obligation to pursue non-aggression against a Soviet ally. Because of the threat of Soviet intervention from the north, on February 16, Chinese authorities declared that it was also prepared to go to war with the Soviet Union. By this time, the bulk of Chinese forces (some 1.5 million troops) were concentrated along the northern border, while 300,000 Chinese civilians in these border regions were evacuated.