Drawing the Dragon's Claw: China Declares Territorial Sea Baselines in the Gulf of Tonkin

The Chinese Government issued a declaration defining straight baselines between Hainan and Vietnam on 1 March 2024. In doing so, it has completed the definition of baselines off the western side of Hainan through to the terminus of the China-Vietnam land boundary on the coast. Straight baselines can be declared where the coast is complex as a result of coastal indentations or the presence of a fringe of islands along and close to the coast. They provide a simplified baseline along the coast from which to measure maritime zones. Straight baselines can also push the outer limits of the territorial sea further seaward than if `normal' baselines are used. This article outlines China's recent announcement regarding its territorial sea baselines as well as the limits delineated from them and considers it in light of international jurisprudence and State practice on baselines. It is anticipated that China's new baselines system will not impact on the already agreed China-Vietnam maritime boundary in the Gulf of Tonkin but that China will likely face criticism about the manner in which it has drawn these baselines although there is currently little prospect of a dispute reaching international adjudication.