[14] The conflict had a lasting impact on the relationship between China and Vietnam, and diplomatic relations between the two countries were not fully restored until 1991, following the withdrawal of Vietnamese troops from Cambodia and the dissolution of the Soviet Union.

[22] As the French did not have the means to immediately retake Indochina, the major powers agreed that the British would take control and troops would occupy the south while Nationalist Chinese forces would move in from the north.

Finally, on 20 July 1954, the Geneva Conference resulted in a political settlement to reunite the country, signed with support from China, the Soviet Union, and Western European powers.

During the initial stages of the First Indochina War with France, the recently founded communist People's Republic of China continued the Soviet mission to expand communism.

[36]: 94 Following the death of Mao in September 1976, the overthrow of the Gang of Four and the ascent of Deng Xiaoping, the Chinese leadership revised its own positions to become compatible with market aspects, denounced the Cultural Revolution, and collaborated with the US against the Soviet Union.

In the eyes of the People's Republic of China, the growing Soviet-Vietnamese relationship was a disturbing development; they feared an encirclement by the less-than-hospitable Soviet sphere of influence.

Instead, the South held a separate election that was widely considered fraudulent, leading to continued internal conflict with communist factions led by the Viet Cong that intensified through the late 1950s.

With supplies and support from the Soviet Union, North Vietnamese forces became directly involved in the ongoing guerrilla war by 1959 and openly invaded the South in 1964.

The People's Republic of China started talks with the United States in the early 1970s, culminating in high level meetings with Henry Kissinger and later Richard Nixon.

The People's Republic of China, on the other hand, also supported the Maoist Khmer Rouge against Lon Nol's regime during the Cambodian Civil War and its subsequent take-over of Cambodia.

[36]: 96 On 8 July 1978, the General Political Bureau of the Vietnamese People's Army released orders to adopt an offensive strategy against China, including attacking and counterattacking within and beyond the border.

[36]: 96 On 25 December 1978, Vietnam invaded Democratic Kampuchea, overrunning most of the country, deposing the Khmer Rouge, and installing Heng Samrin as the head of the new Cambodian government.

[38]: 56 Beginning in fall 1978 and continuing through early 1979, Deng Xiaoping made a series of international trips, one goal of which was to gauge world opinion on the issues between China and Vietnam.

[51] Deng sought an endorsement from the United States in order to deter the Soviet Union from intervening when China launched a punitive attack against Vietnam.

[38]: 56  According to United States National Security Advisor Zbigniew Brzezinski, Carter reserved judgment, an action which Chinese diplomats interpreted as tacit approval.

[52] According to academic Suisheng Zhao, "[t]he proximity in the timing of the military thrust against Vietnam, was to take advantage of the normalization to bluff the Soviets with a nonexistent US endorsement.

[54] The 17 February issue of People's Daily accuses Vietnam of discrimination against ethnic Chinese populations, of preparing to invade China, and of shooting at civilians and their properties from across the border on its front page.

Another article, also on the front page, claims that the Foreign Ministry sent a diplomatic note expressing "the strongest protest" for Vietnamese incursions on Chinese soil.

[58] The PLA quickly advanced about 15–20 kilometres into Vietnam, with fighting mainly occurring in the provinces of Cao Bằng, Lào Cai and Lạng Sơn.

After capturing the northern heights above Lạng Sơn, the PLA surrounded and paused in front of the city in order to lure the VPA into reinforcing it with units from Cambodia.

To prepare for a possible Chinese invasion, the Central Military Commission of the Communist Party of Vietnam ordered all armed forces across the border to be on stand-by mode.

[63] During the withdrawal, the PLA used a scorched-earth policy, destroying local infrastructure and looting useful equipment and resources (including livestock), which severely weakened the economy of Vietnam's northernmost provinces.

Analysts claimed that regardless of the outcome of the combat, China had managed to permanently divert Vietnamese troops, supplies, attention, and energy to the border region.

In the spring of 1979, the authorities expelled approximately 8,000 Hoa people from Hanoi to the southern "New Economic Zones", and partially resettled the Hmong tribes and other ethnic minorities from the northernmost provinces.

In response to the defection of Hoàng Văn Hoan, the Communist Party of Vietnam removed from its ranks pro-Chinese elements and persons who had surrendered to the advancing Chinese troops during the war.

[79] However, China caused Vietnam to suffer from serious economic and military hardship by threatening to launch a second invasion, and by supporting Pol Pot guerrillas in Cambodia.

"[81] In contrast, Vietnam's decreasing prestige in the region led it to be more dependent on the Soviet Union, to which it leased a naval base at Cam Ranh Bay.

[88][89][90] The Vietnamese state newspaper Nhân Dân claimed that Vietnam suffered more than 10,000 civilian deaths during the Chinese invasion[91][92] and earlier on 17 May 1979, reported statistics on heavy losses of industry and agricultural properties.

These vary from the patriotic song "Bloodstained Glory" originally written to laud the sacrifice and service of the Chinese military, to the 1986 film The Big Parade which carried veiled criticism of the war.

[99] During the war, there were numerous patriotic songs produced to boost the nationalism of Vietnamese people, including "Chiến đấu vì độc lập tự do" ("Fight for Independence and Freedom") composed by Phạm Tuyên, "Lời tạm biệt lúc lên đường" ("Farewell When Leaving") by Vu Trong Hoi, "40 thế kỷ cùng ra trận" ("40 Centuries We Fought Side By Side") by Hong Dang, "Những đôi mắt mang hình viên đạn" ("The Eyes Shaped Like Bullets") by Tran Tien and "Hát về anh" (Sing for you) by The Hien.