History and Reality of Entanglement between China and the Philippines in Second Thomas Shoal

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2023-09-14 | Chen Xiangmiao

Second Thomas shoal, located in the range of 9 degrees 39 '-9 degrees 48' north latitude and 115 degrees 51 '-115degrees 54' east longitude, is an important part of the Spratly Islands, 17 kilometers long from north to south and more than 5 kilometers wide from east to west, and 17 nautical miles and 19 nautical miles from Mischief Reef and Boxall Reef of Spratly Islands, respectively. Second Thomas shoal is an atoll with a lagoon of about 33.09 square kilometers inside the reef. Scientific investigation and satellite remote sensing suggest that the deepest depth of the lagoon in the Second Thomas shoal is 27 meters. The surrounding reef is dotted by intermittent rocks visible at low tide, but most of the reef is submerged by water no more than 2-3 meters deep. The lagoon is connected to the sea through a channel about 130 meters long and 10 meters wide to the southwest. 

Second Thomas Shoal


No Dispute Over the Sovereignty of Second Thomas Shoal


Though the naming of Second Thomas shoal was quite a complicated process, China was the first country to name it officially and incorporate it into its administrative territory.

In May 1788, British captain Thomas Gilbert sailed a merchant ship named Charlotte from Port Jackson, Australia, in an attempt to open up a new shipping route to China. He was accompanied by the merchant ship Scarborough and its captain, John Marshall. After a voyage of more than 180 days, the ship finally arrived in Huangpu, Guangzhou, China. According to information disclosed by the British Hydrographic Office, during the passage through the South China Sea, the fleet, in accordance with the usual practice, named the islands and reefs hitherto unknown to them after the names of the merchant ships and captains. Therefore, the Second Thomas shoal was named after Captain Thomas Gilbert, that is, the 'Second Thomas Reef.' Similarly, Xinyi Reef was called the ‘First Thomas Reef,’ and Heping Ansha was called the ‘Third Thomas Reef.’ According to extant archival information, this is the earliest name for Second Thomas shoal in the Western world.

This is not the first time that the Western world has named islands and reefs in the South China Sea according to such principles. Many documents prove that the British merchant ship Scarborough was wrecked on Huangyan Island in February 1748, following which it was named "Scarborough Reef". Of course, this is the second "Scarborough" merchant ship in British history.

The discovery and naming of Second Thomas shoal by China predates the 18th century. According to the Genglu Book, recorded in local dialect and handed down from generation to generation by Chinese fishermen based on their long-term and continuous fishing practices in the South China Sea, Second Thomas shoal is called "Broken section". This name vividly describes the fact that the southern half of the Second Thomas shoal is broken into several unconnected sections and naturally presents a discontinuous shape. This practice of naming according to shape is not unusual, as seen with “Xinyi Reef” in Spratly Islands. This naming practice strongly proves the long history of Chinese fishermens’ fishing activities in the South China Sea. In the absence of modern technological support such as sky photography and remote satellite sensing, the precise shape of the islands and reefs can only be confirmed by long-term, uninterrupted exchanges of activities. The “Genglu Book” was formed no later than China's Ming Dynasty, that is, in the 16th century or earlier. For example, the Portuguese in the 16th century named Yongxing Island as “Poxo”, which is a transliteration of the name from Genglu Book.

In 1935, in the Comparison Table of Chinese and English Names of Islands in the South China Sea published by the Chinese government, Second Thomas shoal was named “Thomas Second Beach”, and the exact location was clearly marked in the Map of Islands in the South China Sea published by the Chinese government at the same time. In 1947, the Chinese government published the Comparison Table of Old and New Names of the South China Sea Islands, which was reviewed and revised again, and named Second Thomas shoal as “Ren 'ai Hidden Sands”. In 1983, the Chinese government again published the Standard Names of Some South China Sea Islands, and officially named it as Ren 'ai Reef. In 1987, during the comprehensive survey of Nansha Islands organized by the Chinese government, a comprehensive scientific research team landed on Second Thomas shoal and erected Chinese stone tablets and markers. 

According to the 1898 Treaty of Paris between the United States and Spain, the 1900 Treaty of Washington between the United States and Spain, as well as the 1930 Convention between the United States and Great Britain and their exchange of note regarding the maritime boundary between the Philippine Archipelago and the State of North Borneo, the westernmost part of the Philippine territory was at 116 degree East longitude. However, Second Thomas shoal is located at 115 degrees East longitude, which is not within the territory of the Philippines at all.[1]


The Aground Incident in 1999 was Self-directed and Staged by the Philippines.


On May 9, 1999, the Philippine Navy’s tank landing ship Sierra Madre sailed to the Second Thomas shoal. The Philippine government claimed that the ship’s bottom was leaking and it had to “land” on the reef flat of the northwest side of the reef. This is the root cause of the series of maritime conflicts between China and the Philippines over the Second Thomas shoal.

Second Thomas Shoal and the Philippine Navy’s tank landing ship Sierra Madre


The Philippines was the first country to occupy the islands and reefs of China’s Nansha Islands located within the dotted line of the South China Sea. In 1970, it first occupied Mahuan Island of China's Nansha Islands. According to Philippine journalist Marites Danguilan Vitug, the erstwhile President of the Philippines Ferdinand Marcos saw the strategic and economic value of the Nansha Islands and reefs, so he secretly organized forces to occupy eight islands and reefs in the Nansha Islands in two waves, occupying five islands and reefs in 1970-1971. In 1977-1978 he occupied three islands and reefs.[2] Second Thomas shoal was illegally occupied during the third wave of Philippines' “occupation” of islands and reefs in the South China Sea directed by the Estrada administration, of which then Philippine Defense Secretary Olli Mercado was the direct decision-maker. According to Mercado’s recollection, in response to a proposal by a senior general of the Philippine Armed Forces to remove markers on reefs claimed by China, he said that "there is no need to report", and he also said that China’s “slowly advancing occupation” must be monitored. The then chief of naval staff, Eduardo Mario R. Santos, suggested that World War II-era tank landing ships could be sailed to the reef and anchored on it to establish a presence in the name of the Philippine government.[3] According to public information, this was the first time that the Philippines proposed the concept of a “aground strategy.” The Philippines chose Second Thomas shoal mainly because it is located within the Philippines’ 200-nautical miles exclusive economic zone and is only 22 nautical miles away from Mischief Reef under China’s actual control. At the same time, Second Thomas shoal is only a testing ground for the Philippines' “agound strategy”. 

In May 1999, the Philippine Navy's tank landing ship Sierra Madre became the first casualty of the “ aground strategy”. The reason for this is related to the ship’s service years and combat functions. Sierra Madre originally belonged to the US Navy, commissioned in 1944, had participated in the war against Japan in the Western Pacific during the Second World War, the Vietnam War. The ship was decommissioned in Guam in October 1970 and served in the Navy of South Vietnam until 1976, when it was handed over to the Philippine Navy. The Sierra Madre tank landing ship has experienced many important wars, which can be described as making outstanding battle achievements, but it is also “aging”. 

However, the average design life of US ships is about 40 years, with some ships such as amphibious landing ships having a longest life of more than 50 years. Nevertheless, it was 55 years after its service from 1944 to 1999, during which it was retired and repaired twice. And according to the judgment of Philippine journalist Maritez Tangilan Vitugu’s photos, the state of the Sierra Madre when it was “landing on the shoal” was not bad.[4] It has been disclosed that the so-called “water leakage” by the Philippines refers to the seepage of water from the top ceiling of the ship caused by seawater corrosion, long-term docking and lack of maintenance, and this does not hinder the ship’s action. The so-called “water leakage under the ship” by the Philippines is probably a fabricated excuse for “landing on the beach”. 

It is worth noting that at that time, the Philippine Ministry of National Defense even proposed to build a prefabricated lighthouse on Second Thomas shoal, and planned to copy the “Second Thomas shoal model” to Huangyan Island in November 1999, but had to give up due to different opinions within the Philippine government and China’s preventive measures inadvance.[5]


China Has Made as Friendly an Arrangement as Possible on the Issue of Second Thomas Shoal 


It should be pointed out that at present, there is no officially published document indicating that the Philippines had clearly “actually occupied Second Thomas shoal” when it carried out the “ship grounding” operation in 1999.

For a long time after 1999, the Philippines, through diplomatic statements and other means, tried to interpret the “landing shoal” triggered by such “accident” as an extension of territorial sovereignty and an actual occupation. Luisto Fernandez, who took over as Philippine Secretary of Defense in 1999, confidently said later that the ship had touched the bottom of the Second Thomas shoal, and no matter how shabby it was, it would be an extension of Philippine territory and unsinkable. On August 9, 2023, Philippine Coast Guard spokesman Tarella declared that the Philippine government will never give up the “Sierra Madre” because it is a symbol of Philippine sovereignty in the “West Philippine Sea” area.[6] On the same day, Philippine National Security Council spokesman Jonathan Malaya admitted that the 1999 “landing” act was intentional and deliberate.[7] The subtext of the Philippine government’s recent remarks is an attempt to confirm the illegal occupation of Second Thomas shoal. In addition, the Philippine government has also asserted recently that the “landing shoal” precedes the Declaration on the Conduct of Parties in the South China Sea (DOC), so there is no violation of the DOC,” in order to justify its unilateral act.[8]


Two logical doubts need to be cleared up here: One is that “no new occupation of the islands and reefs” and “restoring the natural state of the Second Thomas shoal” are at least reflected in the package of basic preconditions and principles that China and ASEAN countries established when starting to formulate a Code of conduct in the South China Sea. In December 1997, China and ASEAN countries held their first summit meeting. At the request of ASEAN leaders, the Joint Statement of the ASEAN-China Summit issued after the meeting specifically stressed that “all relevant parties agreed to continue to exercise restraint and handle relevant differences in a calm and constructive manner”. Under the pretext of “monitoring China” and “strengthening its presence”, the Philippines’ “aground strategy“ on the Second Thomas shoal and Huangyan Island has violated its own commitments and the consensus reached with other countries in the region, and undermined the basic norms governing international relations.

On the other hand, the Philippines’ extension of the “landing shoal” on Second Thomas shoal to the so-called illegal “occupation” undoubtedly violates the basic consensus affirmed in the Declaration on the Conduct of Parties in the South China Sea (DOC). The “restoration of the natural state of Second Thomas shoal” has been the tacit agreement of the Philippines when it signed the DOC.

The Declaration on the Conduct of Parties in the South China Sea (DOC) signed in 2002 states that "the parties undertake to exercise self-restraint, refrain from taking actions that may complicate, escalate or affect peace and stability of disputes, including abdicating from taking habitation actions on currently uninhabited islands, reefs, shoal, sand or other natural structures, and to manage their differences in a constructive manner." This is the basic consensus already established before the consultations were launched in 1999. 

Facts show that even though the Philippine side has repeatedly violated regional consensus and commitments, China has been making proper arrangements for conflicts over the Second Thomas shoal with “as much good-will as possible” in view of maintaining peace and stability in the South China Sea and minimizing the "South China Sea factor" in China-Philippines relations.

Since 1999, China has never stopped protesting the Philippines’ “agrounding” on Second Thomas shoal. However, at the same time, China has offered to adopt a “temporary special arrangement” to allow the Philippines to provide humanitarian supplies for the personnel on board on Second Thomas shoal. According to Santos himself, there were 22 marines who participated in the “landing” mission on Second Thomas shoal in May 1999. Since then, the Philippines has kept at least seven marines on board on a rotating basis. It is estimated that Philippine supply ships carry out an average of one replenishment operation at Second Thomas shoal every month. While replenishing supplies, the Philippine Marines are rotated every two to three months on average.[9] The “temporary special arrangement” on Second Thomas shoal is a tacit understanding between China and the Philippines based on full mutual trust and long-term on-site interactions at sea. The provision and rotation of Philippine marines on Second Thomas shoal benefit from this tacit understanding and is also a product of China’s principle of “as much goodwill as possible”.

In addition, China’s principle of “as much goodwill as possible” is also reflected in the restraint of its maritime actions. The “temporary special arrangement” is based on mutual trust between China and the Philippines. It contains at least two preconditions: First, the Philippine side should not carry materials that are not humanely needed, including construction materials, in its resupply operations; Second, the two sides should maintain effective communication on the replenishment operations in a timely manner, in particular, to jointly confirm the types and nature of supplies. The Philippines has promised on more than once that they would not to reinforce ships. In May 2013, then Philippine Defense Secretary Gazmin assured China that the Philippines had no plans to build infrastructure on Second Thomas shoal, and that the resupply operation was only to provide food and water for soldiers. “These ships are also used for troop rotation, and we can’t put people there permanently, they will go crazy,” he said.[10] However, the Philippine government and opposition have been constantly calling for the establishment of permanent structures on Second Thomas shoal, and there is sufficient evidence to show that the Philippines has never stopped sending construction materials and other supplies to the reef that go far beyond the scope of humanitarian supplies.[11] China is not unaware of this. The Chinese side has always been patient to persuade, guide and urge the Philippines to honor its promises through timely deterrence and diplomatic representations, and has avoided taking measures that could escalate tensions between the two sides.


Rethinking the Causes and Ways out of the Ups and Downs of the Second Thomas Shoal Dispute

“The South China Sea dispute is not the whole story of bilateral relations”, as the 2023 Joint statement between China and the Philippines emphasized. However, since the beginning of this year alone, the two countries have engaged in at least two conflicts over the Second Thomas shoal that have drawn wide attention from the international community. This lays bare the necessity for both sides to rethink on the reasons behind the dispute and the way out. China and the Philippines didn’t lack experience in handling emergencies on the Second Thomas shoal, and also established a smooth and efficient communication mechanism that has been proven by practice. In addition to the annual vice-ministerial bilateral consultation mechanism on the South China Sea issue, a direct hotline for border and maritime affairs between the foreign ministries was established in early 2023, which provides a basis for the two sides to conduct crisis management in a timely manner and avoid information asymmetry.

However, the experience and the role of the mechanism cannot be brought into play without the efforts of the two countries and the support of positive external factors. Carrying more than humanitarian supplies is the main internal factor that has led to the recurrence of “old wounds” in the China-Philippines Second Thomas shoal conflict. In particular, in accordance with the relevant consensus in the Declaration on the Conduct of Parties in the South China Sea (DOC), China and the Philippines should meet each other halfway on the restoration of the Second Thomas shoal. 

External factors are the incitement and deliberate misdirection of some countries. In April 2023, Admiral Samuel Paparo, commander of the U.S. Pacific Fleet, publicly stated that the United States was ready to help the Philippines resupply Second Thomas shoal. On August 5, a US State Department statement specifically reiterated that an armed attack on Philippine public vessels, aircraft, and armed forces, including its coast guard in the South China Sea, would trigger the US mutual defense commitment under Article IV of the 1951 US Philippines Mutual Defense Treaty. The US is not a littoral state in the South China Sea, nor a party to the disputes. Its position on the issue of the Second Thomas shoal is essentially a game with “no cost”, and it bears unshirkable responsibility for the escalation of relevant maritime disputes between China and the Philippines. 

The dispute between China and the Philippines over the Second Thomas shoal reflects one aspect of relevant disputes in the South China Sea, that is, conflicting territorial claims over some islands and reefs of the Nansha Islands, which is beyond the jurisdiction of the arbitral Tribunal for the so-called South China Sea Arbitration. Experience in Asia has proved that sincere and friendly dialogue and consultation between parties directly concerned is the best way to resolve relevant maritime and land disputes. The Philippines should work with China to manage maritime dispute instead of dragging down the development of the regional situation.



[1] Treaty of Peace between the United States of America and the Kingdom of Spain (Treaty of Paris), signed in Paris, December 10, 1898.
[2] Vitug M D. Rock Solid: How the Philippines won its maritime case against China[M]. Ateneo de Manila University Press, 2018, chapter 2.
[3] Ibid.
[4] Ibid.
[5] Ibid.
[6] 'We will not leave Ayungin Shoal', the Manila Times, August 9, 2023, https://www.manilatimes.net/2023/08/09/news/national/we-will-not-leave-a...
[7] Ibid.
[8] Joyce Ann L. Rocamora and Priam Nepomuceno, PH to China: Sierra Madre ‘permanent station’ in Ayungin Shoal, August 8, 2023, https://www.pna.gov.ph/articles/1207375?__cf_chl_tk=L06JtYLKFoWOU5X7bmQq...
[9] China raises concerns over PH’s reported development plans on Ayungin Shoal, Philippine Daily Inquirer, July 04, 2022, https://globalnation.inquirer.net/75939/china-raises-concerns-over-phs-r....
[10] Alexis Romero, China fears PH may build structures in Ayungin Shoal, The Philippine Star, May 30 2013,
[11] Build Sustainable Permanent Structures On Ayungin Shoal, Chiz Urges DND, Chiz Escudero, December 5, 2021, https://chizescudero.com/build-sustainable-permanent-structures-on-ayung...

Chen Xiangmiao

Chen Xiangmiao is an associate research fellow in the National Institute for South China Sea Studies, and a Ph.D candidate of Nanjing University. He worked as a visiting scholar in the RSIS of Nanyang Technology University of Singapore in 2014. His research focuses on South China Sea issue and regional security studies. He is a column writer of Lianhe Zaobao (based in Singapore) and China-US focus. His recent articles include Can the US-China Conflict or Confrontation in the SCS be avoidable, ASEAN’s Interest and policy on the South China Sea issue, and etc.