China’s U-shaped Line as a Claim to Maritime Space?

By Huy Duong

China's nine dash line from Beijing's perspective. Huy Duong argues that interpretations of China's claim as one including all maritime space within this area are not supported by international law. Source: CSIS SEAP's flickr photostream, all rights reserved.

In 1948 China published a map titled “South China Sea Islands Location Map” with a U-shaped line, but to date it has not clarified the line’s meaning. While the obvious interpretation of this line is a claim to the islands, events since the 1990s have raised concerns that China might claim all the maritime space it encloses.

Three interpretations of the U-shaped line as a claim to maritime space have been advanced.

  1. Taiwan claims that the area enclosed by this line is historical waters. However, there is no evidence that China has historically exercised sovereignty over this area.
  2. China’s notes verbales to the Commission on the Limit of the Continental Shelf in 2009 includes a map with the U-shaped line, without stating that this line demarcates any maritime area. These notes verbales seem to support the interpretation that China claims the area inside the U-shaped line as EEZ. However, analyses such as those by CSIS’ South China Sea in High Resolution program would reject such a claim.
  3. According to the third interpretation, China’s claims are in three layers. First, China claims the islands. Second, China claims the EEZ generated by those islands, which might not extend as far as the U-shaped line. Finally, China claims “historic rights” to a share of marine resources, with the U-shaped line being either the limit or both the basis and the limit for this claim.

For the “historic rights” claim to be valid, China must have acquired rights over the area inside the U-shaped line prior to UNCLOS, and those rights must have been preserved by that Convention.

Could China have acquired such rights from the U-shaped line itself? China has never declared that that the U-shaped line represents a claim to rights over the maritime space enclosed. No rights can be derived from a line that has never been declared as a claim to such rights.

Could China have acquired such rights from traditional fishing activities? Even if traditional fishing could potentially create historic rights in certain areas of the South China Sea, it is unlikely that UNCLOS preserves such rights for the entire area inside the U-shaped line. Furthermore, since Chinese fishermen were not the only fishermen who traditionally fished in the South China Sea, China would not have a monopoly of any historic rights derived from traditional fishing.

Additionally, in the Libya-Tunisia Continental Shelf Case, the International Court of Justice stated that historic rights derived from traditional fishing stemmed from a legal regime distinct from that of the continental shelf and were not relevant. Traditional fishing does not justify continental shelf claims to the extent of the U-shaped line.

Could China have acquired such rights from any of its pre-UNCLOS declarations? When Indonesia, Malaysia and the Philippines made claims to the continental shelf in this area in the 1960s, when Indonesia and Malaysia signed a demarcation agreement in 1969, and when South Vietnam made claims in 1971, China did not protest. China started to make claims to the continental shelf concerned in the 1990s. Therefore China has little basis for claiming pre-UNCLOS rights over this continental shelf.

All three interpretations of the U-shaped line as a claim to maritime space lack legal basis. Only the interpretation of the U-shaped line as a claim to islands is reasonable. The relative merits of the conflicting island claims should be determined according to international law of territorial acquisition. Claims over maritime space should be derived from the disputed islands using UNCLOS and jurisprudence on maritime delimitation, and not from the U-shaped line.

Mr. Huy Duong contributes articles on the South China Sea to several news outlets including the BBC and Vietnam’s online publication VietNamNet.


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