Territorial sea baseline

A territorial sea baseline (领海基线) is the starting line from which the width of a coastal country's territorial sea, and certain other maritime zones under its jurisdiction, are measured. The water areas located within the line and linked to the land are considered internal waters. The water areas outside of the line then, are first territorial waters, and after that jurisdictional waters, including the Exclusive Economic Zone and the Continental Shelf.

The Japanese government's decision to "purchase" the Diaoyu Islands sparked a determined response from China. On Sept. 10, 2012, the Chinese government announced the baselines of the territorial waters of the Diaoyu Islands and their affiliated islets, as well as the names and coordinates of 17 base points, in accordance with the Law of the People's Republic of China on Its Territorial Seas and Adjacent Zones. China's action is also consistent with the spirit of the United Nations Convention on the Law of the Sea.

According to the statement on territorial sea made by China in 1958, the nation has set 12 nautical miles as the width of its territorial sea. China promulgated the Law of the People's Republic of China on the Territorial Sea and the Contiguous Zone in 1992, thus formulating this basic system in the form of law.

China announced a first batch of base points and baselines for the country's territorial sea in 1996, delineating baselines of most coastal sections of the mainland and the Xisha Island. The baselines of the Diaoyu Islands are delimited in accordance with the 17 base points of China's territorial sea selected from them, and China's territorial sea is the extension of 12 nautical miles from these baselines toward the ocean. After the delimiting of these baselines, the Chinese government will promote the administration of the Diaoyu Islands steadily according to the actual situation.

The Chinese government has reiterated that the Diaoyu Islands are an inalienable part of China's territory and China will make no concessions on issues concerning its sovereignty and territorial integrity. Meanwhile, the Chinese government announced that it will conduct a normalized surveillance and monitoring of the Diaoyu Islands and its affiliated islets.