China–Vietnam border

[4] It then proceeds overland in a broadly eastwards direction, albeit in a highly irregular zig-zag pattern, predominantly through isolated mountainous areas inhabited by ethnic minorities.

China under the Han dynasty had established control over Nam Việt (northern Vietnam) by the early 1st century BC.

[5][6] The Vietnamese of Tonkin managed to break free of Han rule in 939 AD, forming the kingdom of Đại Việt.

China's commissioners were Chou Te-jun (Zhou Derun 周德潤), and Teng Ch'eng-hsiu (Deng Chengxiu 鄧承修).

[citation needed] The French commission was led by M. Bourcier Saint-Chaffray, and its members included M. Scherzer, the French consul in Canton, Dr Paul Neis, a noted Indochina explorer, Lieutenant-Colonel Tisseyre, Captain Bouinais, and M. Pallu de la Barrière (though the latter took no part in the commission's work).

[citation needed] In preparation for the commission's work General de Courcy despatched French troops to occupy Lạng Sơn, That Khe and other border towns in October 1885.

[citation needed] Demarcation work began in late 1885 and was completed in 1887, the latter the same year that Tonkin was incorporated into the colony of French Indochina.

[citation needed] A dispute over two areas on the border between Yunnan province and Tonkin was settled by the award of Meng-suo (猛梭) and Meng-lai (猛賴) to Vietnam and the transfer of a large tract of fertile arable land between Ma-pai-kuan (馬白關) and Nan-tan-shan (南丹山) to China.

[citation needed] A Convention confirming the new border between Vietnam and China was signed in Peking on 26 June 1887 by French and Chinese representatives.

[3]: 95  A second round of negotiations in August 1978 was also unsuccessful because of the Youyi Pass Incident in which the Vietnamese army and police expelled 2,500 refugees across the order into China.

[26] Neither of the agreements signed by the two parties are recognized by the Republic of China on Taiwan and continues to claim the territory, as reflected in its official maps.