Relations between Vietnam and China (, pinyin: Zhōng Yuè Guān Xì; ) have been extensive for millennia, with Northern Vietnam especially under heavy Sinosphere influence during historical times. Despite their Sinospheric and socialist background, centuries of conquest by modern China's imperial predecessors as well as modern-day tensions have made relations occasionally wary.Forbes, Andrew. "Why Vietnam Loves and Hates China". Asia Times. 26 April 2007. Retrieved 15 March 2013."China: The Country to the North". Forbes, Andrew, and Henley, David (2012). Vietnam Past and Present: The North. Chiang Mai: Cognoscenti Books. ASIN: B006DCCM9Q. The modern relationship has been marked with extensive economic, political and cultural ties, as well as territorial disputes in the South China Sea.

China and Vietnam have lengthy historical connections, including nearly a thousand years during which Vietnam was a dependency of China. Vietnam emerged from the disintegration of China's Tang dynasty in the 900s. Subsequently, China supported the Trần dynasty while the Ming dynasty established a tributary relationship with Vietnam. In 1884, after Chinese defeat in the Sino-French War, Vietnam under the Nguyễn dynasty became a protectorate of France, marking the end of formal Chinese influence on Vietnam. During the Cold War, the People's Republic of China (PRC) ruled by the Chinese Communist Party (CCP) assisted North Vietnam and the Communist Party of Vietnam (CPV) during the Vietnam War whilst the Taiwan-based Republic of China (ROC) was allied with South Vietnam.

Following the fall of Saigon in 1975 and the subsequent Vietnamese reunification as the Socialist Republic in 1976, relations between the two countries started to deteriorate. Vietnam ousted the Khmer Rouge, a party that China propped up which had become genocidal, from power in Cambodia. China invaded Vietnam in February 1979, beginning the Sino-Vietnamese War. China perceived Vietnam's domination over Indochina from Vietnam's historical legacy (emperor Minh Mạng) whilst Vietnam desired Vietnamese-friendly neighbors (Laos and Cambodia) on its immediate western borders. Cross-border raids and skirmishes ensued, in which China and Vietnam had a series of border and naval clashes from 1979 to 1990. The two countries officially normalized diplomatic ties in 1991.

China and Vietnam share a border. The two countries remain in dispute over political and territorial issues in the South China Sea. Since the normalization of diplomatic ties, both sides have since worked to improve their diplomatic and economic relations. The two countries have been striving for restraint as well as present and future stability. The two countries signed a comprehensive strategic partnership in 2008. China and Vietnam maintain extensive economic ties, with the Vietnamese economy becoming increasingly connected with China's. As two ruling communist parties of socialist states, the CCP and CPV maintain close political and ideological ties.

History China and Vietnam have lengthy historical connections, including nearly a thousand years during which Vietnam was a dependency of China. As a result, Vietnam was influenced by Chinese literature, scholarship, modes of family organization, civil administration, and bureaucratic practices.

Early history

The earliest reference of the proto-Vietnamese in Chinese annals was the Lạc (Chinese: Luo), Lạc Việt, or the Dongsonian, an ancient tribal confederacy of perhaps polyglot Austroasiatic and Kra-Dai speakers who occupied the Red River Delta in northern Vietnam. China and Vietnam had contact since the Chinese Warring States period and the Vietnamese Thục dynasty in the 3rd century BC (disputed), as noted in the 15th-century Vietnamese historical record Đại Việt sử ký toàn thư. Between 111 BC and 939, Vietnam was subject to three separate periods of imperial Chinese domination although it successfully asserted a degree of autonomy with the Khúc clan in 905 and later independence with the establishment of the Ngô dynasty in 939. In 968, Đinh Bộ Lĩnh declared himself emperor of the Đinh dynasty, however Vietnam nominally remained a vassal of China until the 19th century. Vietnam was again ruled by China under the Ming dynasty from 1407 until the establishment of the Lê dynasty in 1428.

According to the old Vietnamese historical records Đại Việt sử ký toàn thư and Khâm Định Việt Sử Thông Giám Cương Mục, An Dương Vương (Thục Phán) was a prince of the Chinese state of Shu (蜀, which shares the same Chinese character as his surname Thục), sent by his father first to explore what are now the southern Chinese provinces of Guangxi and Yunnan and then to move their people to what is now northern Vietnam during the invasion of the Qin dynasty.

Some modern Vietnamese scholars believe that Thục Phán came upon Âu Việt, which is now northernmost Vietnam, western Guangdong, and southern Guangxi Province, with its capital in what is today Cao Bằng Province). After assembling an army, he defeated Hùng Vương XVIII, the last ruler of the Hồng Bàng dynasty, in 258 BC. He proclaimed himself An Dương Vương ("King An Dương"), renamed his newly acquired state from Văn Lang to Âu Lạc and established the new capital at Phong Khê (now Phú Thọ, a town in northern Vietnam), where he tried to build Cổ Loa Citadel, the spiral fortress approximately ten miles north of his new capital.

Han Chinese migration into Vietnam has been dated back to the era of the 2nd century BC, when Qin Shi Huang first placed northern Vietnam under Chinese rule (disputed), Chinese soldiers and fugitives from Central China have migrated en masse into northern Vietnam since then and introduced Chinese influences into Vietnamese culture. The Chinese military leader Zhao Tuo founded the Triệu dynasty, which ruled Nanyue in southern China and northern Vietnam. The Qin governor of Canton advised Zhao to found his own independent kingdom since the area was remote, and there were many Chinese settlers in the area. Under the Eastern Han dynasty, the Chinese prefect of Jiaozhi, Shi Xie, ruled Vietnam as an autonomous warlord and was posthumously deified by later Vietnamese emperors. Shi Xie was the leader of the elite ruling class of Han Chinese families that immigrated to Vietnam and played a major role in developing Vietnam's culture.

Imperial period

Vietnam emerged from the disintegration of China's Tang dynasty in the early 900s. The border between China and Vietnam was generally stable for the next 800 years, with China challenging the border once.

China invested the Trần dynasty (1225–1400) as Vietnam's rulers. The Trần's control of Vietnam weakened in the 1390s and in 1400, Hồ Quý Ly deposed the Trần ruler and declared himself the founder of a new dynasty. The Trần requested that China's Ming dynasty intervene on its behalf. The Ming sent troops and envoy to re-establish the Trần and quickly defeated Hồ. The Ming subsequently deemed the Trần to be in disarray and instead reclaimed Vietnam as its own territory. Subsequent Ming emperors returned the relationship to a tributary with a Vietnamese ruler in Vietnam.

According to a 2018 study in the Journal of Conflict Resolution on Vietnam-China relations from 1365 to 1841, they could be characterized as a "hierarchic tributary system" from 1365 to 1841. During Vietnam's Đại Việt period (968–1804), the Vietnamese court explicitly recognized its unequal status compared to China through explicit institutional mechanisms. Vietnam conducted its relations with China through the tributary system. During this period, Vietnam was primarily focused on addressing its domestic instability and its external relations generally focused to the south and west, including with the Champa kingdom, among others.

In 1884, during Vietnam's Nguyễn dynasty, the Qing dynasty and France fought the Sino-French War, which ended in a Chinese defeat. The Treaty of Tientsin recognized French dominance in Vietnam and the protectorate treaty France signed with Vietnam, spelling the end of formal Chinese influence on Vietnam and the beginning of Vietnam's French colonial period.

Both China and Vietnam faced invasion and occupation by Imperial Japan during World War II, and Vietnam languished under the rule of Vichy France. In the Chinese provinces of Guangxi and Guangdong, Vietnamese revolutionaries, led by Phan Bội Châu, had arranged alliances with the Chinese Nationalists, the Kuomintang, before the war by marrying Vietnamese women to Chinese National Revolutionary Army officers. Their children were at an advantage since they could speak both languages and so they worked as agents for the revolutionaries, spreading their ideologies across borders. The intermarriage between Chinese and Vietnamese was viewed with alarm by the French. Chinese merchants also married Vietnamese women and provided funds and help for revolutionary agents.

Late in the war, with Japan and Nazi Germany nearing defeat, US President Franklin Roosevelt privately decided that the French should not return in Indochina after the war was over. Roosevelt offered the Kuomintang leader, Chiang Kai-shek, all of Indochina to be under Chinese rule, but Chiang Kai-shek reportedly replied, "Under no circumstances!" In August 1943, China broke diplomatic relations with Vichy France, with the Central Daily News announcing that diplomatic relations were to be solely between the Chinese and the Vietnamese, with no French intermediary. China had planned to spread massive propaganda on the Atlantic Charter and Roosevelt's statement on Vietnamese self-determination to undermine the French authority in Indochina.

World War II and aftermath

The Chinese Kuomintang provided support to both the Việt Nam Cách mệnh Đồng minh Hội (Viet Cach) and the Việt Nam Độc lập Đồng minh (Viet Minh) in their struggle against Japanese forces.

After the Second World War ended, a United Nations mandate, had 200,000 Chinese troops, led by General Lu Han, sent by Chiang Kai-shek to Indochina north of the 16th parallel to accept the surrender of Japanese occupying forces. The troops remained in Indochina until June 1946. The Chinese supported the Việt Nam Quốc Dân Đảng and Viet Cach to put pressure on the communist-led Viet Minh. Nevertheless, Chinese occupational forces allowed Ho Chi Minh's Democratic Republic of Vietnam (established in 1945) more influence than their British counterparts in the south. Chiang Kai-shek threatened the French with war to force them to negotiate with Ho Chi Minh. In February 1946, Chiang forced the French colonists to surrender all of their concessions in China and to renounce their extraterritorial privileges in exchange for withdrawing from northern Indochina and for allowing French troops to reoccupy the region.

Cold War

First Indochina War and Vietnam War