Under this possible interpretation, the dashed line indicates only the islands over which China claims sovereignty. It is not unusual to draw lines at sea on a map as an efficient and practical means to identify a group of islands. If the map depicts only China’s land claims, then China’s maritime claims, under this interpretation, are those provided for in the LOS Convention. China’s statement accompanying the map in its 2009 Notes Verbales could be read to support this meaning:
China has indisputable sovereignty over the islands in the South China Sea and the adjacent waters, and enjoys sovereign rights and jurisdiction over the relevant waters as well as the seabed and subsoil thereof (see attached map).
The “sovereignty” over the waters “adjacent” to the islands could refer to the 12-nm territorial sea, which is indeed a zone of “sovereignty” under international law.28 Likewise, the “sovereign rights and jurisdiction” could be understood to refer to the legal regimes of the EEZ and continental shelf under the LOS Convention, which uses the same terminology to describe coastal State authority within those zones.29 The “relevant waters” and the “seabed and subsoil thereof” likewise could be understood to refer to the EEZ and continental shelf.
Support for this interpretation can be found in China’s laws and statements. Article 2 of China’s 1992 territorial sea law claims a 12-nm territorial sea around the “Dongsha [Pratas] Islands, Xisha [Paracel] Islands, Nansha (Spratly) Islands and other islands that belong to the People’s Republic of China.”30 China’s 1958 Territorial Sea Declaration makes similar claims.31 With respect to the “relevant” areas seaward of the territorial sea, China’s 1998 EEZ and continental shelf law establishes a 200-nm EEZ and describes China’s continental shelf rights and jurisdiction.32 Indeed, China’s 2011 Note Verbale clarified its view that “China’s Nansha Islands is fully entitled to Territorial Sea, Exclusive Economic Zone (EEZ), and Continental Shelf,” and no mention was made of any other maritime claims.33
Cartographic evidence and official statements also provide support for an interpretation that China’s dashed line describes island claims and not distinct maritime claims. As noted above, the original 1930s dashed-line map, on which subsequent dashed-line maps were based, was titled “Map of the Chinese Islands in the South China Sea.” That map was apparently brought into use domestically by the Republic of China in the late 1940s during a time when the international law governing maritime claims by most accounts recognized only a narrow belt of territorial sea. Indeed, China’s own Declaration on its territorial sea of 1958 states:
This provision [a 12-nm territorial sea] applies to all territories of the People’s Republic of China, including the Chinese mainland and its coastal islands, as well as Taiwan and its surrounding islands, the Penghu Islands and all other islands belonging to China which are separated from the mainland and its coastal islands by the high seas [emphasis added].34
The reference to “high seas”—maritime space under no country’s jurisdiction—separating China’s mainland and coastal islands from “all other islands belonging to China” indicates that in 1958 China made no claim to the entirety of the ocean space within the dashed line.