Beijing sees Manila's demand for defining maritime rights in the South China Sea before confirming the sovereignty of the reefs, along with its other arbitration demand, as a contravention of the common principles of international law used to resolve maritime disputes. Therefore, Beijing believes any arbitration based on Manila's demand will give a direct or indirect verdict on the sovereignty of the South China Sea reefs, which will create the impression that the maritime boundary line has already been drawn.

The standard international practice is to allow a country's land sovereignty to determine its sovereignty over the abutting waters. China's claim in the South China Sea is based both on its "historic rights" in accordance with its U-shaped line demarcating its maritime boundary and the rights it enjoys according to the UN Convention.

Since the 1940s China has time and again marked its U-shaped maritime line confirming its sovereignty over the islands reefs and shoals within the line. More importantly, China's sovereignty over these islands, reefs and shoals was confirmed long before the Convention was signed and came into effect.

Given its sovereignty over these islands, reefs and shoals and its historic ownership of the adjacent archipelagoes, China has the right to regard the low-tide dry reefs and heights near Nansha Islands as an integral part of its maritime territory.

According to Article 298 of the Convention, when signing, ratifying or acceding to the Convention or at any time thereafter, a country can declare that it does not accept the "mandatory procedures" that may act as a binding force on the disputes involving historic bays or titles. When such a dispute arises after the Convention came into effect and where no agreement within a reasonable period of time is reached through negotiations between the parties, a country having made such a declaration shall, at the request of any party to the dispute, accept submission of the matter to conciliation under Annex V, Section 2. But any dispute that involves the concurrent consideration of any unsettled dispute over sovereignty or other rights over continental or insular land territory shall be excluded from such submission.

The Philippines has been occupying China's Nansha Islands and reefs since the 1970s and carrying out illegal activities in the surrounding waters to explore for and exploit resources. This makes unreasonable Manila's move to seek international arbitration in the South China Sea dispute because its sovereignty dispute over specific islands and reefs with Beijing has not been settled and involves Beijing's historic rights.

Manila's move does not have legal sanction also because in a statement to the UN secretary-general in 2006, in accordance with the norms of the Convention, China said it will not accept any mandatory arbitration in the disputes over its maritime boundaries, historic bays or titles.

The author is a professor of international law at the Party School of the Central Committee of the Communist Party of China.