Are China and Vietnam on collision course over Beijing’s ‘creeping’ demarcation in Gulf of Tonkin?

Analysts say China’s move may not comply with international maritime conventions, adding that Beijing’s “creeping” encroachment shows that it is aiming to assert greater control over an important body of water.

On March 1, Beijing released a statement showing a set of seven base points that, when connected, form the baseline for its territorial claims in the Gulf of Tonkin, known as Beibu Gulf in China.

The demarcation is in line with the Law on the Territorial Sea and Contiguous Zone promulgated by China in 1992, according to Chinese state tabloid The Global Times, citing the ministry’s Department of Boundary and Ocean Affairs.

The department said on its official WeChat account that the move was necessary to exercise China’s sovereignty and jurisdiction.

“This new baseline could complicate earlier agreements and other day-to-day maritime activities and endeavours such as fishing,” he warned, adding that some maritime experts are concerned that the new Chinese baseline might be a violation of Unclos.

“If things change from the current demarcation line agreement between the two countries, that might be a worse set of circumstances for Vietnam. You would think Hanoi would need to defend its current entitlements by challenging China’s baseline,” Lee-Brown added.

Isaac Kardon, a senior fellow at the Asia Program at the Carnegie Endowment for International Peace based in Washington, DC, said Vietnam may not have reacted because of a maritime agreement signed by the two countries two decades ago.

“This change amounts to a clarification of the jurisdictional status of [China’s] waters within boundaries already agreed by the two parties in their 2004 maritime boundary and fisheries zone treaty,” Kardon said.

The agreement followed years