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China sought to punish Vietnam, yet both sides claimed victory in the short but bloody war.

On February 17, 1979, troops from the People’s Republic of China attacked the Socialist Republic of Vietnam in what became known as the Sino-Vietnamese War. Although for many years China and the regime in Hanoi had been allies, “as close as lips and teeth,” this “marriage of convenience” slowly began to fall apart beginning in the 1970s when China was unable to match the Soviet Union in military support to Hanoi.

During the First Indochina War (1946-54), Chinese military advisers had played an important role in the Viet Minh victory over the French. With the beginning of the Second Indochina War (1956-75), Hanoi accepted support from both China and the Soviet Union in its struggle to reunify North and South Vietnam by force of arms. During the war in Southeast Asia, China also supported the communist Khmer Rouge in Cambodia (as well as the Pathet Lao in Laos). The Vietnamese Communists and the Khmer Rouge normally cooperated during the war, but there were, nevertheless, a number of border clashes between Vietnam and Cambodia dating back to 1971.


The Vietnam-Cambodia border conflicts continued sporadically until 1975, when relations began to deteriorate after Pol Pot came to power in Cambodia, which was renamed Democratic Kampuchea after the fall of Phnom Penh. The Khmer Rouge demanded that certain areas of land along the Cambodia-Vietnam border be returned to Cambodia and that all Vietnamese leave these areas that the Khmer Rouge claimed Vietnam had taken centuries earlier. Vietnam refused, claiming that this territory had always been part of Vietnam dating back nearly three centuries.

In May 1975, naval patrols from Cambodia and Vietnam clashed in the vicinity of Phu Quoc Island, on their sea boundary. The next month, the Vietnamese attacked the Cambodian bases on Poulo Wai Island. This situation was somewhat diffused when both sides agreed to negotiate; however, the talks accomplished little and the subsequent lull in the conflict was short-lived.

After the fall of Saigon in April 1975, Hanoi had increasingly turned to the Soviet Union for support. In the midst of the ongoing Sino-Soviet split, China was very concerned about this development. The leaders in Beijing were worried about the growing Soviet influence in the region. Accordingly, China increasingly leaned toward Cambodia as a counterweight to the Soviets and Vietnamese in Southeast Asia, ultimately sending military advisers to work with the Khmer Rouge forces.

The border dispute between Vietnam and Cambodia reached a new pitch in April 1977 when Khmer Rouge forces attacked towns in six Vietnamese provinces that bordered Cambodia. At one point, the Cambodians drove four kilometers into Vietnam and occupied part of An Giang province. The Cambodians continued their raids and artillery attacks on Vietnamese towns and villages for the rest of the month and into May. The Vietnamese responded by moving troops into the area to combat the Cambodian troops. In June, the Vietnamese proposed negotiations, but the Cambodians responded with a counterproposal. Each side ignored the other’s call for talks and both continued their military preparations.

In September 1977, Cambodian forces increased their raids into Vietnam, attacking six villages in Dong Thap province while three divisions from the Cambodian Eastern Military Region pushed into Tay Ninh province to a depth of 10 kilometers. There they massacred more than a thousand Vietnamese civilians. Vietnam responded with a counterattack that pushed the Cambodian forces several kilometers back into Cambodia.

In December 1977, Vietnam launched a limited attack against the Cambodian forces that occupied Vietnamese territory. The Vietnamese forces, numbering more than 30,000 troops, pushed the Cambodian forces back, but failed to retake all the occupied area. Cambodia responded by suspending diplomatic relations with Vietnam.

Meanwhile, Vietnam stepped up its support for the Cambodian guerrilla army of Heng Samrin (the Kampuchean National United Front for National Salvation, KNUFNS), which was trying to overthrow the Pol Pot regime. This only increased the tensions between Hanoi and Phnom Penh. Phnom Penh completely broke off diplomatic relations with Hanoi, and each side resorted to a war of words against the other. At the same time, the conflict between Vietnam and China grew.

Vietnam began a new collectivization scheme in March 1978 that led to the exodus of ethnic Chinese from Vietnam, angering Beijing. Meanwhile, a series of disputes and confrontations occurred between China and Vietnam along their common border. The rift between the two increased as Vietnam tilted toward more cooperation with the Soviets. In the summer of 1978, Vietnam joined the Soviet-dominated Council for Mutual Economic Assistance (COMECON) and signed a Treaty of Friendship and Cooperation with the Soviet Union. These events further angered the Chinese, who claimed that the new treaty was a military alliance and part of the Soviet global strategy to marginalize China’s influence. At the root of the conflict between China and Vietnam was China’s concern about Vietnam’s ambitions in Southeast Asia and its growing reliance on the Soviet Union. China branded Vietnam the “Cuba of the East” and denounced the Vietnamese as “tools of Soviet hegemonism.”

Meanwhile, the normalization of relations between China and the United States worried the Vietnamese, who were afraid that the new relationship gave the Chinese confidence to stand up to the Vietnamese and their Soviet patrons. Vietnam saw China as a growing threat to Vietnamese interests in the region. It believed that China would reinforce the military potential of its adversary in Cambodia and might even attack Vietnam directly.

Things had gotten progressively worse along the Cambodia-Vietnam border. Cambodian refugees from the Eastern Zone had poured across the border to escape the earlier fighting. Pol Pot saw this as an insurrection against the Khmer regime and sent forces in to suppress the “uprising.” The suppression, relocation and massacre of those living along the border, including ethnic Vietnamese who lived in the area, convinced Hanoi that it was time to act. Politburo authorized a military operation to solve the Cambodian issue once and for all.

The first phase of the operation, which Defense Minister Vo Nguyen Giap called a “strategic offensive” designed “to exterminate the enemy and seize control,” began on December 21, 1978, when two Vietnamese infantry divisions attacked out of the Central Highlands, driving along Route 19 to seize Stung Treng on the Mekong River. The second phase of the operation began on December 25 when Hanoi launched a full-scale invasion of Cambodia with over 12 divisions, totaling 100,000 troops. The Vietnamese ground forces, supported by the Vietnamese air force, struck across the border into northeastern Cambodia. In one attack, Vietnamese troops attacked west from Tay Ninh province along Route 7. Additional Vietnamese forces took Kampong Cham, while another column attacked west along Route 1 in the direction of Phumi Prek Khsay, the Mekong River gateway to Phnom Penh. The final Vietnamese thrust drove west from Ha Tien, Vietnam, to seize the ports of Kampot and Kampong Som to prevent the resupply by sea of retreating Khmer Rouge forces.

By January 5, 1979, the main Vietnamese spearheads had driven to the eastern banks of the Mekong River. After a brief pause, the Vietnamese forces crossed the river and launched a direct assault on Phnom Penh. The Khmer Rouge leaders elected not to defend the city and it fell on January 7. The Vietnamese forces continued their attack to the west, driving toward the Thai border.

On January 7, 1979, the Vietnamese took possession of all government buildings in Phnom Penh and installed a new government under Heng Samrin. By this time, most of the Khmer Rouge forces had withdrawn into less accessible areas, from which they launched an insurgency against the new government and the Vietnamese forces that stayed to consolidate Hanoi’s hold on Cambodia. By early February, it was clear that Vietnamese forces were not going to withdraw and would in fact continue to occupy Cambodia.


Vietnam’s occupation of Cambodia directly threatened Chinese interests in the region. China could not sit idly by while the Vietnamese had their way in Cambodia. Beijing sent several thinly veiled warnings to Hanoi, but Vietnamese officials responded by agreeing to discuss long-standing “border/ territorial issues” only, refusing to address the presence of Vietnamese troops in Cambodia, which was the main point of contention in the escalating tensions between the two countries.

The invasion of Cambodia and the ouster of the pro-Beijing Pol Pot regime ultimately proved to be the final straw for China, which condemned the invasion of Cambodia and the installation of Heng Samrin as “Vietnamese hegemonism abetted by Soviet social-imperialism.” The growing antipathy between China and Vietnam was further exacerbated by what China saw as persecution of 200,000 ethnic Chinese (Hoa) in Vietnam. There was some truth to this charge; Vietnamese Chinese were stripped of their citizenship and forfeited their rights to own businesses and hold public office. This only added to the rapidly worsening situation. Several Chinese officials were quoted as saying that China was probably going to have to “teach Vietnam a lesson.”

On February 15, 1979, Chinese paramount leader Deng Xiaoping publicly announced China’s intention to strike back at the Vietnamese invasion of Cambodia. At dawn on the morning of February 17, the Chinese People’s Liberation Army (PLA) launched a “punitive” expedition against Vietnam, attacking at numerous points along the 480-mile Sino-Vietnamese border after a massive artillery and rocket barrage. (See Sino-Vietnamese War map, p. 46.)

The overall commander of the PLA forces was General Xu Shiyou, a member of the Politburo and a longtime supporter of Deng Xiaoping. Xu’s deputy, General Yang Dezhi, was in tactical control of the operations. Yang also had been the deputy commander of Chinese troops during the Korean War, during which he had developed the tactics of infiltration and envelopment followed by mass attacks. Yang was chosen to take tactical control due to the similarity of the terrain in northern Vietnam to that in Korea.

Once the attack was joined in earnest, Beijing, concerned about Soviet reaction to the invasion, issued statements to deter Soviet intervention, justifying the action by claiming that it was in response to repeated violations of Chinese territory by Vietnamese troops. Furthermore, Beijing announced that Chinese troops would stay in Vietnam only for a short while and that talks should be initiated to resolve the border conflict as soon as possible.

In response to the Chinese attack across the border, the Soviets sent several naval vessels to Vietnamese waters and initiated a Soviet arms lift to Vietnam. The Soviet military attaché in Hanoi threatened that the USSR would “carry out its obligations under the Soviet-Vietnam treaty,” but Moscow made it clear to Beijing that it would not intervene as long as the conflict remained localized along the common border between China and Vietnam.

The Chinese appear to have had several reasons for launching the attack. First, China wanted to punish Vietnam for the invasion of Cambodia and the toppling of the Pol Pot regime. They hoped that their massive attack would force Vietnam to withdraw troops from Cambodia and thereby remove the pressure on Pol Pot’s forces there. Second, the invasion was designed to deter extension of Vietnamese power across the border into China. Whether this threat was real or not was irrelevant; the Chinese made several statements reiterating their claims that there had been Vietnamese incursions into Chinese territory and that China would defend its territory and people from any Vietnamese aggression. Third, China was concerned about increasing Soviet influence and power in Southeast Asia. By attacking Moscow’s key ally in the area, Beijing could cast doubt on the extent of Soviet power in the region and thus avoid a direct threat to China while dealing a blow to Soviet prestige.

The invading force included 11 Chinese armies of regular ground troops and militia from the Kunming, Chengdu, Wuhan, and Guangzhou military regions. It is thought that troops from Fuzhou and Jinan military regions also participated; if this is true, it means that troops from six of China’s 11 military regions were involved in the campaign. Estimates of the total number of Chinese troops committed range from 200,000 to 450,000. The attacking forces included about 200 tanks and massive amounts of supporting artillery.

After the initial broad thrust across the border, the Chinese attack focused on three objectives: Lang Son, Cao Bang and Lao Cai. Arrayed against the attacking Chinese forces were about 15 Vietnamese combat regiments controlled by four regular divisions – a total force of about 50,000 augmented by local militia and border guards. Most estimates put the total number of Vietnamese defenders at around 130,000.

The initial Chinese plan was to forge a shallow penetration all along the front, hoping to draw into battle and destroy the regular Vietnamese divisions, which the Chinese felt would be compelled to react to protect the provincial capitals and important communication centers that were threatened by the advance. This would result in major battles of attrition in which Chinese forces would inflict heavy punishment on the Vietnamese defenders.

The main Chinese attack appeared to be against Lang Son, a provincial capital on the hills overlooking the Red River Delta, which lay only about 150 kilometers from Hanoi. The Chinese began their assault against Lang Son with an artillery barrage. After the barrage lifted, Chinese 55th Army attacked to seize Dong Dang and was to continue the attack toward Lang Son. At the same time, Chinese 43d Army initially focused on the Vietnamese positions in the hills around Chi Ma, and after taking the town was to turn northwest to secure its ultimate objective, Lang Son. For the attack on Lang Son, Chinese 54th Army was in reserve, following 55th Army. The plan called for 43d and 55th armies to link up southwest of Lang Son, effectively isolating Vietnamese 3d Division there, where it could be destroyed or forced to surrender.

The Chinese had hoped to fight “battles of quick decision,” but their attacks were conducted in a slow and deliberate manner, normally involving massive frontal attacks that relied upon the weight of numbers and firepower to defeat the Vietnamese defenders. The Chinese also used tanks, which surprised the Vietnamese given the hilly nature of the terrain in the area, but the tanks proved useful in bunker busting.

Chinese 43d Army achieved some success, but 55th Army’s attack was slowed by stiff resistance that employed spoiling attacks, minefields and heavy artillery to disrupt and disorganize the Chinese advance. The terrain favored the Vietnamese defenders, and they occupied hills from which they could place devastating plunging fire on the attackers. Against this resistance, the Chinese were unable to maintain sufficient operational tempo to overcome the Vietnamese. Ultimately, Chinese 54th Army had to be committed to the fight. The reinforcements made the difference, but even so, the battle for Lang Son was not over until March 5.

On the Cao Bang front, the attack began on February 17 with Chinese 41st and 42d armies attacking on two separate axes of advance toward the town. These forces would be supported by elements of 12th, 20th and 50th armies. The force allocated to this front numbered around 200,000 troops.

Chinese 41st Army was to cross the border and attack Cao Bang from the north, while 42d Army was to attack it from the southeast. As on the Lang Son front, the Chinese advances were slow and deliberate against stiff Vietnamese resistance. Chinese 42d Army made some progress, but the cost was high; in one engagement, the Vietnamese knocked out a number of Chinese tanks. As at Lang Son, the terrain favored the greatly outnumbered Vietnamese defenders, and they made the Chinese pay for every inch they advanced. Eventually, the sheer numbers of Chinese troops prevailed and Cao Bang fell on February 25. Heavy fighting continued on the Cao Bang front for the next five days, but on March 3, Chinese forces from the Cao Bang and Lang Son fronts linked up at Duet Long, on Highway 4, effectively closing the gap between the two Chinese thrusts.

On the Lao Cai front, the Chinese had attacked with elements of three armies, more than 125,000 troops. Chinese 11th Army attacked across the border from the northwest to seize the town of Phong Tho, about 65 kilometers from Lao Cai, to prevent reinforcement from the west. At the same time, 13th and 14th armies attacked south to seize Lao Cai itself. The Vietnamese defenders in this area included six regiments, totaling about 20,000 troops. As on the other fronts, the out numbered Vietnamese troops put up a stiff defense; after five days, the Chinese had advanced only a few kilometers. The Chinese employed human wave attacks to overcome the Vietnamese positions, but the battle continued until March 5 when Lao Cai fell to the attackers.

While the main Chinese thrusts focused on Lao Cai, Cao Bang and Lang Son, several supporting attacks were conducted elsewhere along the China-Vietnam border. Many of these attacks resembled the larger Chinese operations. For example, in Quang Ninh, on the eastern edge of the border, a platoon of Vietnamese held up an attack on Cao Ba Lanh Mountain for five hours, inflicting 360 casualties on the attacking Chinese force that numbered over 2,800 men.

The day after the Chinese captured Lang Son, Beijing declared that the gate to Hanoi was open; that the Vietnamese had been sufficiently chastised; and announced that it was withdrawing its forces. By March 16, all Chinese forces had crossed the border back into China, blowing bridges and railroads and generally laying waste to the Vietnamese countryside along the way.


The Chinese had hoped to win a quick decision against the Vietnamese, but they found out that their troops were no match for the better-trained and combat-experienced Vietnamese and that they only succeeded when their forces outnumbered the defenders. The Chinese had used outdated and obsolete equipment, some dating back to World War II and/or the Korean War, and their tactics were slow and deliberate. Rather than pursue the infiltration and envelopment tactics that had proved so successful in Korea, the PLA had most often turned to massive frontal assaults that were both wasteful and ineffective.

Part of the problem was an antiquated command and control system that continually demonstrated issues with coordinating combined arms. Chinese artillery relied upon centralized planning and was not responsive to the support needs of the front-line troops. PLA communications were inadequate; few modern radios were available and forward units often resorted to runners to relay orders. Consequently, the Chinese had great difficulty in coordinating large-scale attacks.

Logistics was also a major problem. PLA transport resources were inadequate and the Chinese frequently had great difficulty supplying their troops, often relying on local militia for logistics. Under these conditions, commanders repeatedly lost large numbers of troops to achieve minimal gains. The personnel system, which was based on each Chinese military region being relatively autonomous, was unresponsive, proving unable to provide sufficient replacements for the many casualties the Chinese suffered.

Just how many casualties were incurred on each side is not clearly known. The Vietnamese claimed that the Chinese had lost 62,500 killed in action, but the Chinese only admitted to losing 20,000 total casualties. Harlan W. Jencks, a noted expert on the PLA, estimates that the Chinese lost more than 18,000 soldiers killed in the bitter fighting. The Chinese claimed that the Vietnamese had suffered more than 50,000 casualties, but most Western observers put the number at 20,000-35,000. Although the numbers remain disputed, it is clear that the Vietnamese forces incurred heavy casualties but at the same time inflicted a heavy toll on the Chinese attackers.

By the end of the campaign, the Chinese army had clearly demonstrated shortcomings in organization, equipment, command and control, and tactics that had to be addressed if the PLA was to become an effective and modern force. As New York Times reporter Drew Middleton wrote in the conflict’s aftermath, “The Chinese army had numerical superiority over Vietnam in almost every category – men, guns, tanks – but it was unable to score the smashing victory that it sought because of the relatively slow pace of an offensive carried out by what was basically a marching army.” After the war was over, Deng Xiaoping used the outcome of the bitter fighting to push through a number of measures meant to reform and modernize the PLA.

Both sides claimed victory, but for the Chinese, the campaign to punish Vietnam had not turned out the way Beijing had expected. In assessing the outcome of the war, Gerald Segal concluded in his 1985 book Defending China that it was a complete failure: “China failed to force a Vietnamese withdrawal [from Cambodia], failed to end border clashes, failed to cast doubt on the strength of the Soviet power, failed to dispel the image of China as a paper tiger, and failed to draw the United States into an anti-Soviet coalition.”

However, some observers claim that the campaign may not have been a total loss for China. In the 2001 book Modern Chinese Warfare, 1795-1989, Bruce A. Ellerman suggests that Beijing had launched the attack into Vietnam to expose Soviet assurances of military support to Vietnam as “a fraud.” “Seen in this light,” Ellerman writes, “Beijing’s policy was actually a diplomatic success, since Moscow did not actively intervene, thus showing the practical limitations of the Soviet-Vietnamese military pact.” Banning Garrett and Nayan Chanda agree that China had been successful in demonstrating that the USSR was a “paper polar bear” because it had not come to the aid of the Vietnamese.

The Chinese may have achieved a diplomatic victory, as Ellerman suggests, but it appears that China was the overall loser militarily in the confrontation with Vietnam along their common border. The Chinese had taken all their military objectives, but Vietnam had stood against the Chinese onslaught and clearly demonstrated that it continued to be a power to be reckoned with. As for Vietnam’s relationship with the Soviet Union, the conflict only strengthened Hanoi’s ties with Moscow. As for Cambodia, Vietnam did not withdraw its troops and would continue to occupy the country until October 1991. Thus, in the final analysis of the 1979 Sino-Vietnamese War, the question is “Who taught whom a lesson?”


James H. Willbanks is an “ACG” advisory board member and the editor or author of 13 books, including “Abandoning Vietnam,” “The Battle of An Loc,” “The Tet Offensive: A Concise History,” and “A Raid Too Far: Operation Lam Son 719 and Vietnamization in Laos.”

Originally published in the September 2014 issue of Armchair General.