An estimated US$3.37 trillion worth of global trade passes through the South China Sea annually,[1] which accounts for a third of the global maritime trade.[2] 80 percent of China's energy imports and 39.5 percent of China's total trade passes through the South China Sea.[1] Claimant states are interested in retaining or acquiring the rights to fishing stocks, the exploration and potential exploitation of crude oil and natural gas in the seabed of various parts of the South China Sea, and the strategic control of important shipping lanes. Maritime security is also an issue, as the ongoing disputes present challenges for shipping.[3]
In 1734, the Velarde map was published, showing the territory of the Philippines under the Spanish colonial government.[4][5] The 1808 and 1875 editions of the Carita General del Archipelago Filipino was afterwards published.[4][5][6] In the 1898 Treaty of Paris between Spain and the United States, a map was attached showing parts of the region. The treaty lines were retroactively modified through the 1900 Treaty of Washington.[4][7][8] A US-UK Treaty was signed in 1930 regarding Brunei, Malaysia, and the Philippines.[9]
In 1932, France formally claimed both the Paracel and Spratly Islands for the French Union, rather than French Indochina.[10][11] On 6 April 1933, France occupied the Spratlys, announced their annexation to the French Union,[12][13] and not as part of French Indochina.[14][15][10] Japan protested, but China only protested France's claim on the Paracels, not the Spratlys. In 1932, China sent a Note Verbale to France, stating that the Paracels was the "southernmost territory" of China.[14][15] China reiterated in 1934 that its southernmost territory was limited to the Paracels.[16][17][18][19]
In 1947, the Republic of China, the government of then China, announced the majority of the South China Sea was its territory with a so-called "eleven-dash line". In 1949, the incoming government of China, which overthrew the Republic of China in the Chinese Civil War, announced that it had inherited this claim. The PRC later removed two of its dashes in the Gulf of Tonkin amidst warming ties with Ho Chi Minh's North Vietnam[20][21] However, the Taiwanese (ROC) government continues to use the eleven-dash line to this day.[22][23] Between 1990-1997,[24][25][26] China published three volumes of its ancient maps, where the southernmost territory was Hainan island.[27][9][16][17]
A 1970s memorandum from US National Security Advisor Brent Scowcroft to then US President Ford highlighted that China, Vietnam, Taiwan, and the Philippines all claimed sovereignty over the Spratly Islands. At that time, all of these countries, except the People's Republic of China (PRC), had militarily occupied one or more of the Spratly Islands.[28] In 2013, the PRC began island building in the Spratly Islands and the Paracel Islands region.[29] During a US Senate hearing in May 2015, then US Assistant Secretary of Defense, David Shear reported that in the Spratly Islands, Vietnam had established 48 outposts, the Philippines had eight, China had eight, Malaysia had five, and Taiwan had one. Shear also noted that from 2009 to 2014, Vietnam was the most active claimant in terms of both upgrading outposts and reclaiming land, with approximately 60 acres reclaimed.[30][31] According to Reuters, island building in the South China Sea, primarily by Vietnam and the Philippines, had been going on for decades. And Vietnam, Taiwan, and the Philippines have all deployed military forces on some of their islands, but Vietnam has not stationed any troops on its floating artificial islands. While China had been late to the island-building game, its efforts had been on an unprecedented scale; from 2014 to 2016, it had constructed more new island surface than all other nations have constructed throughout history and (unlike the other claimants) had placed military equipment, at least for a brief period, on one of its artificial islands by 2016.[32] Also, a 2019 report from VOA that compared China and Vietnam's island building campaign in the South China Sea stated that the reason why Vietnam had been subject to little international criticism or support was because of the slower speed and widely perceived defensive nature of its island-building project.[33]
China's actions in the South China Sea have been described as part of its "salami slicing"/"cabbage wrapping" strategies.[34][35] Since 2015, the United States and other states such as France and the United Kingdom have conducted freedom of navigation operations (FONOP) in the region.[36] China has sent a position paper to the international court, reiterating its recognition of the 1898 Treaty of Paris, the 1900 Treaty of Washington, and the 1930 US-UK Treaty, which recognizes Scarborough Shoal and the Spratlys as part of Philippine territory.[37] In July 2016, an arbitration tribunal constituted under Annex VII of the United Nations Convention on the Law of the Sea (UNCLOS) ruled against the PRC's maritime claims in the South China Sea Arbitration.[38] The tribunal did not rule on the ownership of the islands or delimit maritime boundaries.[39][21] The People's Republic of China, as well as Taiwan (unrecognized as an independent sovereign state by all the other claimants), rejected the international ruling.[40] Most claimants, however, agree with the ruling. The Philippines called for the internationally-binding ruling to be respected,[41] while Malaysia and Vietnam positively acknowledged it as part of international law.[42][43] China has continued to pursue its claims in the region,[44] and on 17th June 2024, one of its vessels collided with a Philippine vessel, damaging the vessel and injuring Filipino navy personnel within the internationally-recognized exclusive economic zone of the Philippines.[45][46]
^international Crisis Group (2012). "Appendix B"(PDF). Stirring up the South China Sea (Ii): Regional Responses. International Crisis Group. Note 373, p. 36. JSTORresrep32231.11. Unlike Beijing, however, Taipei uses the original eleven dashes, since the other two dashes in the Gulf of Tonkin were only removed under the approval of Premier Zhou Enlai in 1953, four years after the establishment of the PRC. Li Jinming and Li Dexia, 'The Dotted Line on the Chinese Map of the South China Sea: A Note'.
^"外交部「南海議題及南海和平倡議」講習會媒體提問紀要". Ministry of Foreign Affairs Republic of China (Taiwan) (in Chinese). 8 April 2016. Retrieved 31 October 2021. 十一段線係出現於民國36年(1947年)12月1日由內政部公布之「南海諸島位置圖」
^An Atlas of Ancient Maps in China (1990). Cultural Relics Publishing House, Beijing.
^An Atlas of Ancient Maps in China (1994). Cultural Relics Publishing House, Beijing.
^An Atlas of Ancient Maps in China (1997). Cultural Relics Publishing House, Beijing.