Introduction
This study offers a geographical overview of the characteristics of the South China Sea basin. It is a narrative about the important natural factors that brings to the fore the rationale for the international attention given to this body of water since the 1950s and in particular, since the introduction of the new law of the sea embodied in the provisions of the 1982 United Nations Convention on the Law of the Sea (UNCLOS).1 The narrative includes the topics of the natural continental shelf and slope of the mainland and portion of the Sunda Shelves; the nature of the sedimentation on the sea floor; the tides, tidal streams and surface currents; the geography of the Paracel, Pratas and Spratly Archipelagos in their natural form; and seamounts, underwater volcanoes and the marine environment.
It is wise, at this early stage of the narrative to present the definition given for the limits of the semi-enclosed sea which is the geographical focus of this study. Not only has the definition of this sea, as a semi-enclosed body of water, been debated between geographers and oceanographers on the one hand and the legal fraternity on the other hand but also the marine features contained therein have varied interpretations, so that there are calls to change its name.2 To that end, it is vital to offer a geographical overview of the South China Sea basin in this first chapter of the present volume in order to set the scene for other discussions. The South China Sea basin is surrounded by the coast of the Indo-China/Malay Peninsula to the west, the mainland of China to the northwest, the Strait of Taiwan to the north, the Philippine Archipelago to the east, the island of Borneo to the south and a portion of the Indonesian Archipelago.
The names of States and geographical features used in this chapter will adopt the orthodox English nomenclature as employed, for example, by the International Hydrographic Organisation and the International Hydrographic Chart Series.
Geographical limits of the South China Sea
The geographical limits of the South China Sea basin were defined by the International Hydrographic Bureau (now Organisation) in their Special Publication 23 of 1953.3 However, in a revised draft (as of 17 October 2019) of Limits of Oceans and Seas, 4th edition (1986), the International Hydrographic Organization (IHO) officially recognised the Natuna Sea.4 The geographical coordinates listed hereunder (in degrees, minutes and seconds of arc value) are given as Latitude North (Lat. N) and Longitude East (Lon. E). The southern limit of the South China Sea, IHO code number 6.1, is revised, northward, from the Bangka Belitung Islands to the Natuna Islands. The limits of this semi-enclosed sea, as defined, are reproduced verbatim, as follows:
On the North:
From Jiaowei Cape (20° 13’ 30” N; 109° 55’ 15” E), the southwestern extremity of Leizhou Peninsula, eastward, along the coast of China, to the mouth of Hanjiang River (23° 27’ 30” N; 116° 52’ E); thence a line joining the mouth of Hanjiang River eastward to Changshan Head (23° 25’ 50” N; 116° 56’ 25” E), the western extremity of Nan’ao Island; thence from Changshan Head eastward, along the southern coast of this island, to the south-eastern extremity thereof (23° 23’ 35” N; 117° 07’ 15” E); thence a line joining the south-eastern extremity of Nanao Island south-eastward, along the southern banks of this island, to Eluan Cape (21° 53’ 45” N; 120° 51’ 30” E), the southern extremity of Taiwan Island (the common limit with the Taiwan Strait, southern approach – code number 7.2).
On the East:
A line joining Eluan Cape to the eastern extremity of Amianan Island (21° 06’ 30” N; 121° 57’ 25” E); thence from Amianan Island southward to the eastern point of Balintang Island (19° 57’20” N; 122° 08’ 35” E); thence from Cape Engaño (18° 35’ N; 122° 08” E), the north-eastern extremity of Luzon Island; thence from Cape Engano southward, through Luzon Island, to Fuego point (14° 08’ N; 120° 34’ 30” E), the north-western extremity of Lubang Island; thence from Fuego Point south-westward to Palapag Point (13° 51’ N; 120° 04’ 30” E), the north-western extremity of Lubang Island; thence from Palapag Point south-eastward to Cape Calavite (13° 26’ 45” N; 120° 18’ E), the north-western extremity of Mindoro Island. (From Eluan Cape (Taiwan Island) to Cape Calavite (Mindoro Island: the common limit with the Philippine Sea – code number 7.1); thence from Cape Calavite south-westward to the north-western extremity of Busuanga Island (12°18’ 40” N; 119° 51’ 45” E), and to the northern extremity of Cabuli Island (11°26’ 45” N; 119° 35” E); thence a line joining the southern extremity of Cabuli Island southward to Cabuli Point (11° 25’ N; 119° 30’ E); thence southward, through this island, to the southern extremity thereof (11° 25’ 45” N; 119° 35’ E); thence a line joining the southern extremity of Cabuli Island southward to Cabuli Point (11° 25’ N; 119°30’ E), the north-eastern extremity of Palawan Island; thence from Cabuli Point south-westward, along the western coast of Palawan Island, to Cape Buliluyan (8°20’ 30” N; 117° 10’ 30” E), the southwestern extremity of this island; thence a line joining Cape Buliluyan south-westward to the north-western extremity of Bancalan Island (8° 14’ 50” N; 117° 04’ 50” E); thence from the north-western extremity of Bancalan Island south-westward, through the western side of Secam Island reefs (8° 11’ 40” N; 116° 59’ E), and of the western shoals of Balabac Island (7° 55’ N; 116° 49’ E), to Cape Sempang Mangayan (7° 02’ N; 116° 44’ 45” E), the northern extremity of East Malaysia; from Cape Calavite (Mindoro Island) to Cape Sempang Mangayan (east Malaysia): (the common limit with the Sulu Sea, western approach, code number 6.27); and thence from Cape Semang Mangayan south-westward, along the coasts of East Malaysia and Brunei, to Cape Datu (2° 05’ N; 109° 38’ 20” E), the south-western extremity of East Malaysia.
On the South:
A line joining Cape Datu north-westward to Subi Kecil Island (3° 03” N; 108° 51’ 30” E), thence to Senua Island (4° 00’ 04”; 108° 25’ 20” E), and to Sekatung Island (4° 47’ 50” N; 108° 01’ 25” E), the northern island of Natuna Archipelago; thence from Sekatung Island south-westward to Nanas Reef (3° 19’ 50” N; 105° 35’ E), and to Damar Island (2° 44’ 30” N; 105° 22’ 50” E), in the Anambas Archipelago; thence from Damar Island south-westward to cape Berakit (1° 13’ 50” N; 104° 34’ 10” E), the northern extremity of Bintan Island; from Cape Datu (east Malaysia) to Cape Berakit (Bintan Island): the common limit with the Natuna Sea, code number 6.4); and thence from Cape Berakit north-westward to Horsburgh Lighthouse (1° 19’ 50” N; 104° 24’ 30” E), on the Pedra Branca Rock, and to Cape Penyusop (1° 22’ 10” N; 104° 17’ 05” E), the south-eastern extremity of West Malaysia (the common limit with the Singapore Strait, eastern approaches, code number 6.5).
On the West:
From Cape Penyusop north-westward, along the eastern coast of West Malaysia, to the eastern side of the mouth of Kelantan River (6° 13’ N; 102° 13’ 40” E); thence a line joining the eastern side of the mouth of the Kelantan River north-eastward to Cape Bai Bung (8° 36’ 40” N; 104° 43’ 15” E); the south-western extremity of Viet Nam (the common limit with the Gulf of Thailand, code number 6.3); thence from Cape Bai Bung eastward and northward, along the coast of Vietnam, to Cape Lai (17° 05’ N; 107° 07’ 15” E); thence a line joining Cape Lai, in Viet Nam, north-eastward to Yingge Cape (18° 30’ N; 108° 41’ 30” E), the south-western extremity of Hainan Island, China; thence from Cape Yingge Cape north-eastward, through (?) Hainan island, to Lingao Cape (20° 00’ 30” N; 109° 42’ 40” E), on the north-western coast of this island; and thence a line joining Lingao Cape north-eastward to Jiaowei Cape (20° 13’ 30” N; 109° 55’ 15” E), the south-western extremity of Leizhou Peninsula, China (the common limit with the Gulf of Tonkin, southern approach, code number 6.2). [Emphasis added]
The limits of the basin and its adjacent seas are detailed hereunder. The lengths (in nautical mile (M) and kilometre (km)) of the collective line segments, where applicable, of the limiting lines, as delineated on charts, are listed below. One nautical mile (M), a measurement for distance used by mariners, is equivalent to 1.85 km. The values were obtained by measurement from nautical charts.5
Table 1.1 Length of Limit of South China Sea (Code: 6.1) | Geographical Limit | Km | M | Adjacent Sea (Code) |
| North limit (sector) | 407 | 220 | Taiwan Strait (7.2) |
| East limit (sector) | 444 | 240 | Philippine Sea (7.1) |
| South limit (sector) | 944 | 510 | Natuna Sea (6.4) |
| West limit (sector) | 390 | 210 | Gulf of Thailand (6.3) |
| Northwest limit (sector) | 235 | 127 | Gulf of Tonkin (6.2) |
In the context of this presentation, these are the limits that are adopted for this narrative. Within the prescribed limits the following littoral states, listed by their common form name, are Brunei, China, Indonesia, Malaysia, the Philippines and Vietnam. Clearly, Cambodia, Indonesia, Singapore and Thailand are excluded from the list; however, these countries are often mentioned as littoral states of the South China Sea in the context of territorial disputes and other cultural, economic and social issues. This chapter intentionally avoids the discussion of the claimant states and their territorial disputes as it is purely geographical in content and not geopolitical in intent. Such arguments may be raised in the later chapters of this volume.
