The nameTonkin, written "東京" inchữ Hán characters andĐông Kinh in theVietnamese alphabet, means "eastern capital", and is the formertoponym forHanoi, the present capital of Vietnam. It is not to be confused withTokyo, which is also written "東京" and also means "eastern capital". During theFrench colonial era,the northern region of today’s Vietnam was calledTonkin.
Bắc Bộ is the native Vietnamese name ofTonkin, which is the nowadays region ofNorthern Vietnam. The bay's Vietnamese and Chinese names –Vịnh Bắc Bộ andBěibù Wān, respectively – both mean "Northern Bay".
The Gulf of Tonkin is a relatively shallow portion of thePacific Ocean; the majority of the gulf's ocean floor is less than 75 metres (246 ft) in depth, and no part of the gulf is submerged in more than 100 metres (330 ft) of water.[4]
On 4 August 1964, United StatesPresidentLyndon B. Johnson claimed that North Vietnamese forces had twice attacked Americandestroyers in the Gulf of Tonkin.[5] Known today as theGulf of Tonkin Incident, this event spawned theGulf of Tonkin Resolution of 7 August 1964, ultimately leading to open war between North Vietnam and South Vietnam. It furthermore foreshadowed the major escalation of theVietnam War in South Vietnam, which began with the landing of US regular combat troops atDa Nang in 1965.
Map of the maritime border between Vietnam and China in the Gulf of Tonkin. The red dot is Bach Long Vi Island
On December 25, 2000, Vietnam and China signedan Agreement on the Delimitation of the Gulf of Tonkin. An Agreement took effect on June 30, 2004, officially defining the maritime border between the two countries in the Gulf of Tonkin.[1][6]
The 2025 Vietnamese declaration on the baselines and width of territorial waters, which was made as a response to the parallel 2024 declaration from China. This map is wholly labeled inVietnamese language andtranscription.
On March 1, 2024, China issued a “Declaration on the baselines of the territorial waters in the northern part of the Gulf of Tonkin”.[7][8][9][10] Vietnam calls on China to respect international law.[7][10] One year later, in February 2025, Vietnam also announced baseline for determining its territorial waters width in the Gulf of Tonkin.[11]
Cooke, Nola; Li, Tana; Anderson, James A., eds. (2011).The Tongking Gulf Through History. Philadelphia, PA: University of Pennsylvania Press.ISBN978-0812243369.
Churchman, Catherine (2016).The People Between the Rivers: The Rise and Fall of a Bronze Drum Culture, 200–750 CE. Lanham, MD: Rowman & Littlefield.ISBN978-1442258600.
