Why China’s Claim over the West Philippine Sea is Baseless

Chinese aggression is the gravest external threat to the Philippines since World War Il,” asserted Supreme Court Senior Associate Justice Antonio T. Carpio.

Justice Carpio said that beginning in the late 1988s, China has been gradually encroaching on the West Philippine Sea, the portion of the South China Sea that the Philippines considers its maritime territory. The West Philippine Sea is a composite of the country’s territorial sea, which starts from the coastal baseline extending to 12 nautical miles outward; exclusive economic zone, which starts from the baseline extending to 260 nautical miles outward; and extended continental shelf or the natural extension of the land territory of the coastal state beyond the 202 nautical mile-limit. 

In the Spratly Islands, China seized and subsequently constructed artificial islands on seven reefs that are situated within the Philippines’ exclusive economic zone (i.e., Mischief Reef, Johnson South Reef, and well as within the country’s extended continental shelf (i.e., Subi Reef, Fiery Cross Reef, and Cuarteron Reef). North of the Spratly Islands, China also claimed rights over and cordoned off Scarborough Shoal and Reed Bank to prevent Filipinos from fishing and exploring these grounds. Both Scarborough Shoal and Reed Bank likewise lie within the Philippines’ exclusive economic zone.


The government of China justifies its occupation of the reefs by claiming that these natural Formations, along with the vast expanse of the South China Sea, belong to China.

Justice Carpio noted that in 2013, China submitted its nine-dash line map to the United Nations. Although the nine-dash line has no fixed coordinates, the line encompasses almost the entirety of the South China Sea and shows James Shoot, an area within Malaysia’s exclusive economic zone, as China’s southernmost border. The Chinese government asserts that the nine-dash line map is based on China’s 2,000-your history of naming, exploring, and exploiting the resources of the South China Sea.

Justice Carpio explained that the Chinese government has been peddling this historic claim to the rest of the world in a bid to take control of the South China Sea for economic and military purposes. “China wants all the fisheries, oil, gas, and mineral resources within the nine-dash line.” said Justice Carpio. “The South China Sea is rich in methane hydrates, said to be one of the fuels of the future. China wants to secure alt these methane hydrates for itself as according to China, they can supply China’s fuel requirements for three hundred years.”

Moreover, South China Sea has abundant marine resources that can feed China’s huge population. Justice Carpio said that 80 percent of China’s coastal waters are already polluted and unable to support the annual per capita fish consumption of the Chinese Population, reported to be the highest in the world.

South China Sea also serves as a strategic location for China to display and exercise its military dominance in Asia. Satellite images show that the artificial islands that China constructed are now fully functioning air and naval bases. These bases provide offshore sanctuary to China’s nuclear-armed submarines and other military assets, such as missile launchers, radar systems, and combat-ready aircraft.

Justice Carpio said that China is gearing up to build another manmade island atop the Scarborough Shoal to complete the third point of the triangle in combination with the existing military installations in the Spratly Islands and Paracel Islands. The completion of this triangle will allow China to declare an air defense identification zone (ADIZ) over the South China Sea. ADIZ will effectively extend China’s airspace and enable China to control the mobility of foreign aircraft flying over the South China Sea.


According to Justice Carpio, China’s own historical maps and official documents belie the current Chinese government’s 2,000-year historic claim. He said that official and non-official maps from 1132 (Song dynasty) up to 1912 (Qing dynasty) consistently depicted Hainan Island as the southernmost territory of China. The constitutions of the Republic of China after the collapse of the Qing dynasty (issued in 1912, 1914, 1924, 1937, and 1940 confirm what the cartographic records show—that China’s national border ends of Hainan Island.

Chinese territorial claims in the South China Sea only began to surface in the 1930s. In 1932, the Chinese government issued a Note Verbale to the French government protesting its occupation of the Paracel Islands as the area forms “the southernmost part of Chinese territory.” The Paracel Islands are located south of Hainan Island and are within the exclusive economic zones of both Vietnam and China. In 1948, the Kuomintang government published a map titled Location Map of the South Sea Islands which introduced the eleven-dash fine circling the South China Sea. This map became the basis of the current Chinese government’s nine-dash line claim.

Justice Carpio pointed out that none of these Chinese maps or documents ever acknowledged Scarborough Shoal or the Spratly Islands as part of Chinese territory before the mid-20th century. On the other hand, numerous maps of Southeast Asia and the Philippines dating as far back as the 17th century and various archival records show that the Philippines has stronger historical bases for claiming parts of the South China Sea.

For example, in the 1636 map published by Swiss artis Matthaus Merian, Scarborough Shoal was named “P. De Mandato” or point of command, referring to the presence of Spanish garrison in the area. This shoal was later called “Panacot”—the Tagalog word for threat or danger—in the first scientific map of the Philippines titled Carta hydrographica y chorographica de las Yslas Filipinas, which was published by Jesuit priest, Pedro Murillo Velarde, in 1734. Several other foreign-drawn maps referred to this shoal by the some Tagalog name and placed it within the Philippine territory. Some European cartographers began to refer to it as “Scarborough” after a British seagoing vessel called Scarborough ran aground on one of the shoal’s rocks in 1748. Another Philippine map published by Spanish authorities in 1808 titled Carta General del Archipiélago de Filipinas named the shoal “Bajo de Masingloc o Scarborough.” After Spain ceded the Philippines to the United States under the Treaty of Paris, the US Coast and Geodetic Survey published a map entitled Islas Filipinas, Mapa General Observatorio de Manila, in which the shoal, Bo. Masinloc, is depicted as part of the Philippine territory.

Meanwhile, the 1695 Coronelli Map titled Isole dell’Indie show Spratly Islands as part of the Philippine Archipelago. The 1734 Murillo Velarde Map of the Philippines also feature the rocks and islands of the Spratly, then labelled “Los Bajos de Paragua.”

Aside from these maps, documents such as the 1900 Treaty of Washington recognized islands outside the Treaty of Paris lines, including the Scarborough Shoal, as part of the Philippine archipelago that was relinquished by Spain to the US in 1898. An official communication between US authorities in the 1930s also noted the absence of competing claims from the other governments, reinforcing the Philippines’ rights over the shoal.

Justice Carpio also said that unlike the Philippines, China has no solid documentation that it has previously exercised authority over Scarborough Shoal. A review of the Notice to Mariners issued by American and Philippine authorities from 1960s and 1980s, which served to warn marine vessels of bombing and gunny exercise at the Scarborough Shoal, revealed that not a single country lodged a complaint against these military activities. “We notified the world for free decades and nobody protested; said Justice Carpio. “China never protested.”


Even if China and the Philippines have historic claims over the South China Sea, these have been rendered invalid by the UNCLOS which both countries had signed and ratified. UNCLOS is an international treaty that defines the rights and obligations of countries with regard to the world’s seas and their natural resources.

Under the UNCLOS, it is the coastal state that has legal rights to and jurisdiction over an adjacent body of water. The UNCLOS, in particular, recognizes the sovereign rights of a coastal state over an area extending up to 200 nautical miles from its baseline—what it calls the exclusive economic zone. This means that the coastal state can explore and exploit, conserve, and manage the natural resources within this zone. It also has jurisdiction “with regard to the (i) establishment and use of artificial islands, installations and structures, (ii) marine scientific research; (iii) the protection and preservation of the marine environment” (Article 56, UNCLOS).

These sovereign rights apply to the extended continental shelf of the coastal state as well. if the coastal state chooses not to explore the continental shelf—which encompasses both the exclusive economic zone and the extended continental shelf—or exploit its natural resources, “no one may undertake these activities without the express consent of the coastal State.” (Article 77, UNCLOS).

The low-tide reefs and rocks taken by China within the exclusive economic zone and extended continental shelf of the Philippines are subject to the sovereign right of the Philippines. Mischief Reef, for example, is only 125 nautical miles off Palawan, but 596 nautical miles from China’s southernmost territory, Hainan Island. This geographic proximity grants the Philippines sovereign rights and jurisdiction over these low-tide natural formations based on these UNCLOS guidelines.

China’s appropriation of a large portion of the West Philippine Sea, hence, is a clear violation of the UNCLOS, according to Justice Carpio. “Sovereign rights mean supreme rights, superior to the rights of other states,” he said. “This extinguished all historic rights or claims by other states in the exclusive economic zone of a coastal state.”

Moreover, most of the reefs converted by China into manmade islands were low-tide elevation in their natural state, i.e., above water at low tide but submerged at high tide. UNCLOS does not consider low tide elevation land or territory and as such, is not entitled to territorial sea or airspace. China, thus, cannot claim additional maritime zones out of these illegally occupied artificial islands. “China’s illegal act cannot result in a legal right,” Justice Carpio said.

Apart from infringing on the West Philippine Sea, China is also claiming ownership of the high seas which are part of the global commons. Under UNCLOS and other international agreements, countries are guaranteed freedom of navigation, overflight, fishing, and scientific research on the high seas. “The high seas could not be subjected to sovereignty by any state, whether coastal or landlocked,” Justice Carpio said. “By appropriating for itself the fishery resources in the high seas of the South China Sea, China is committing a grand theft of the global commons.”


The Philippines stands to lose 80 Percent exclusive economic zone and 100 percent of its extended continental shelf if China’s nine-dash line claim remains unchallenged, according to Justice Carpio. This means that the Philippines loses access to precious maritime resources, such as fisheries, gas, and mineral resources. 

Over the past years, the intimidation tactics and blockade implemented by the Chinese navy and militia forces in the Spratly Islands and Scarborough Shoal have driven away Filipino fishermen from their traditional fishing grounds, adversely affecting their livelihood.

Chinese harassment of survey ships in Reed Bank, also forced the Philippines to suspend oil and gas exploration in the area. The Philippine government had previously awarded service contracts to private companies to conduct oil and gas survey in Reed Bank. This was in line with Philippine efforts to develop Reed Bank as a replacement for the Malampaya gas field. The Malampaya gas field, which contains 2.7 trillion cubic feet of natural gas and supplies 30 percent of the electricity needs of Luzon, is projected to be depleted by 2029-2030. The Reed Bank, according to US Geological Survey, may be sitting on as much as 5.4 billion barrels of oil and 55.1 trillion cubic feet of natural gas. Justice Carpio said that the country Will have rotating brownouts if Reed Bank is not developed.

In addition, China’s island-building activities have permanently altered the natural state of the reefs and wrought irreversible damage on the surrounding marine environment and resources. Scientists note that China used gigantic dredgers to cut through and pulverize coral, rock, and seabed, and then dumped these materials over the reefs to form artificial islands. This action destroyed the reefs which serve as the breeding ground of and provide shelter to diverse fish species and other marine life. According to scientists, reef destruction has far-reaching consequences since eggs and larvae produced in the Spratly Islands do not only replenish the fish stocks in the area, but also travel to and repopulate fish communities in the waters of the Philippines, Indonesia, Malaysia, and Thailand.

In January 2013, the Philippines initiated a case against China before the Permanent Court of Arbitration, one of the accepted dispute resolution bodies under the UNCLOS. The Philippines is asking the arbitral tribunal to nullify China’s nine-dash line claim based on historic rights; declare the reefs on which China built artificial islands as low tide elevations or rocks and therefore not entitled to territorial seas or exclusive economic zones, and affirm the Philippines’ entitlement over its exclusive economic zone and extended continental shelf, and declare Chinese interference in the West Philippine Sea as unlawful.

While China officially rejected the arbitration procedure, the arbitral tribunal ruled in 2015 that it has jurisdiction over the case and continued the proceedings even Without China’s active participation. On 12 July 2016, the arbitral tribunal issued its final decision on the case, ruling in favor of the Philippine claim.

“The Philippines today is engaged in a historic battle to defend over 531,000 square kilometers of its maritime space in the West Philippine Sea, an area larger than the total land area of the Philippines of 300,000 square kilometers,” said Justice Carpio. “All citizens of the Philippines—both government personnel and private individuals—have a solemn duty to prevent the loss of this huge maritime space. It is a duty we owe to ourselves, and to future generations of Filipinos.”

Credits to the Joanne B. Agbisit of the Philippine Social Science Council.