Geopolitical Flashpoint
In the vast expanse of the West Philippine Sea, where competing claims intersect with national pride and strategic necessity, the Ayungin Shoal, also known as Second Thomas Shoal, has emerged as a persistent and volatile flashpoint. At the center of this tension lies an unlikely symbol of resistance and resolve: the BRP Sierra Madre, a rusting World War II era landing ship deliberately grounded by the Philippines more than two decades ago. Far from being a relic of neglect, the vessel has become a focal point of regional rivalry. Its continued presence ensures that Ayungin Shoal remains contested and unresolved, demanding patience, endurance, and strategic restraint from both China and the Philippines amid deep uncertainty in the South China Sea dispute.
Located within the Kalayaan Island Group, Ayungin Shoal lies well inside the Philippines’ exclusive economic zone as defined by international law. China, however, asserts a sweeping claim over much of the South China Sea under its so-called Nine-Dash Line, citing historical narratives and maps. While debates over sovereignty persist, the shoal’s recent prominence is not driven by abstract legal arguments alone. Instead, it is shaped by geography, access, resources, and the presence of the Sierra Madre, which anchors competing strategies and transforms the shoal into a test of national resolve.
A Sentry’s Burden
Ayungin Shoal occupies a critical position within the Spratly Islands, sitting astride key maritime routes in an area historically referred to as the Dangerous Ground. This region is notorious for shallow waters, poorly charted reefs, and narrow navigable passages. For much of the twentieth century, mariners were advised to advised to avoid entirely, as it posed both navigational and security risks. Yet beneath these hazards lies strategic value. Early covert hydrographic surveys conducted by major naval powers revealed that control over these internal sea lanes could translate into influence over surrounding waters and nearby features.
The shoal functions as a natural gateway between several contested areas, creating chokepoints that can be monitored or constrained. For China, this offers an opportunity to observe and potentially disrupt Philippine military and civilian maritime activity. For the Philippines, Ayungin Shoal serves as a forward outpost that safeguards access to its westernmost holdings in the Kalayaan Island Group, including Pag-Asa Island. Its proximity to Panganiban Reef, which China occupied and later transformed into a fortified artificial island, heightens its importance. Philippine officials fear that losing Ayungin Shoal would invite a similar transformation, further extending China’s military footprint deeper into the West Philippine Sea.
Geography further compounds these concerns. The shoal lies approximately a few hundred kilometers west of Palawan, the Philippine province closest to the disputed waters. From this vantage point, the Sierra Madre allows Philippine forces to observe Chinese activity around Panganiban Reef and along adjacent sea lanes. Beyond security considerations, the surrounding waters support rich fishing grounds that are vital to food and income security for coastal communities. In 2023, the Bureau of Fisheries and Aquatic Resources reported that nearly half of all illegal, unreported, and unregulated fishing incidents occurred in the West Philippine Sea, with many involving Chinese vessels. These incidents are frequently accompanied by intimidation or expulsion of Filipino fishermen by Chinese Coast Guard ships.
Ayungin Shoal also acts as a strategic buffer protecting Recto Bank, an area believed to hold an estimated 12 billion barrels of oil and 160 trillion cubic fee of natural gas. Control over Recto Bank would offer China a substantial economic and energy advantage. For the Philippines, the stakes are existential. The Malampaya gas field, the country’s sole active natural gas source, is projected to be depleted by 2027. Its decline could reduce Luzon’s power supply by up to forty percent, forcing reliance on imported liquefied natural gas and driving up energy costs nationwide. Within this context, the Sierra Madre bears a disproportionate burden as one of the Philippines’ few fixed footholds in the disputed region.
A Deadly Game of Patintero
The strategic value of Ayungin Shoal shapes the behavior of both China and the Philippines, often in ways that resemble a prolonged contest of movement and denial rather than open confrontation. A useful analogy can be found in patintero, a traditional Filipino game in which players must cross marked lines while avoiding defenders attempting to block their path. In this high-stakes version, Philippine resupply missions play the role of runners, maneuvering through layers of Chinese maritime presence to sustain the small marine detachment aboard the Sierra Madre.
This dynamic has deep roots. In 1995, China’s sudden seizure of Panganiban Reef shocked Philippine lawmakers and defense planners, exposing vulnerabilities in Manila’s approach to the Spratlys. In response, the Philippine Navy deliberately grounded several aging vessels on disputed features as a means of asserting presence. This was criticized and deemed as an act of aggression among Chinese strategic thinkers, citing Filipino journalist Marites Vitug who they argue coined the “aground strategy.” Most of these attempts failed. Vessels placed at Panatag Shoal and near Pag-Asa Island were eventually withdrawn under diplomatic and economic pressure. Ayungin Shoal proved different.
In 1999, the Sierra Madre was run aground on the shoal and has remained there ever since. Though nonoperational and visibly deteriorating, it continues to fly the Philippine flag and host a rotating detachment of marines. Its status as a commissioned warship is central to its deterrent value. Under the United Nations Convention on the Law of the Sea, warships enjoy sovereign immunity and are not subject to seizure. The right to self-defense under the United Nations Charter further reinforces this protection, as does the Philippines’ Mutual Defense Treaty with the United States. Any attempt to forcibly remove the vessel or detain its garrison risks escalation beyond the immediate dispute.
China has sought to undermine this position by challenging the vessel’s legal character, arguing that its condition and lack of mobility strip it of warship status. It has also questioned whether a grounded hulk can constitute a legitimate military outpost. Despite these arguments, the Sierra Madre remains the physical and legal anchor of the Philippines’ claim. Its continued presence explains why China has relied on gray-zone pressure rather than force since 1999, and why Ayungin Shoal remains contested decades after the ship ran aground.
Gray-Zone Tactics
Unable to resolve the issue through direct action without risking broader conflict, China has turned to more calibrated forms of coercion. Maritime confrontations in the area often involve large numbers of Chinese vessels operating in coordinated layers around contested features. This method, described by Chinese military thinkers as the “cabbage strategy,” aims to encircle a target gradually, isolating it without resorting to overt military assault. Over time, the pressure is meant to exhaust the opponent’s ability or willingness to sustain its position.
These actions fall within what are commonly described as gray-zone tactics. They exploit ambiguities in international law and the threshold between peace and armed conflict. Around Ayungin Shoal, this has taken the form of blocking or harassing Philippine resupply missions while avoiding direct attacks on the Sierra Madre itself. The result is a recurring contest of maneuver and endurance, as Philippine vessels attempt to slip through limited sea lanes under constant surveillance.
Physical pressure is reinforced by information and political warfare. Competing narratives are aimed at both domestic and international audiences. In the Philippines, disinformation campaigns often portray Philippine forces as provocateurs, raise fears of war, or frame Manila as merely acting on behalf of the United States. Internationally, China seeks to present its actions as restrained and lawful, even as it incrementally changes conditions on the ground, or in this case, at sea.
In response, the Philippines has adopted a transparency initiative, often inviting journalists and observers during resupply efforts to dispel any narrative in the case of any incident occurring. Combined with consistent statements and diplomatic protests, the Philippines aims to dispel the narratives while also ensuring its aligns with its foreign policy of legalism and multilateralism. This is also supported by the continuous modernization of its security forces to boost its presence, domain awareness, strategic footing, and response capacities.
In summary, these gray-zone measures allow China to test the limits of Philippine resolve and the ambiguities embedded within alliance commitments such as the Mutual Defense Treaty. The objective is not immediate victory but gradual advantage, achieved by shifting expectations and normalizing pressure. Unlike Russia, which has pursued rapid territorial change through overt military force, China’s approach is patient and cumulative. This makes it less immediately explosive but potentially more consequential over the long term.
Risks Amid Uncertainty
The BRP Sierra Madre and Ayungin Shoal sit at the intersection of a wider geopolitical struggle in which no actor openly seeks escalation, yet none are willing to concede ground. While some international analysts warn that intensifying United States–China rivalry raises the risk of confrontation, others argue that the immense political and economic costs of war incentivize restraint. ASEAN states likewise favor the preservation of the status quo, viewing stability in the West Philippine Sea as essential to regional security and prosperity. Consistent with this logic, the Philippines has repeatedly debated calls to fortify or permanently build on Ayungin Shoal. This is like due to the recognition that overt militarization would likely accelerate escalation rather than deter it.
What defines the dispute instead is pervasive uncertainty. Fear, miscalculation, and strategic signaling drive both sides to probe limits without crossing clear red lines. China’s gray-zone tactics represent calculated risks designed to erode Philippine resolve without triggering armed conflict. The Philippines’ decision to ground the Sierra Madre and persist with resupply missions constitutes a parallel strategy of risk acceptance, trading material vulnerability for legal, political, and strategic leverage.
Ayungin Shoal therefore represents a sustained contest of endurance rather than a decisive battle. Each resupply run, blockade attempt, or diplomatic exchange tests patience and resolve on both sides. For the Philippines, the path forward lies not in dramatic escalation but in consistency. This includes sustaining lawful presence, improving maritime domain awareness, strengthening alliance coordination, and reinforcing international support through transparency and legal advocacy.
Over time, the ability to endure pressure while avoiding missteps may prove more decisive than the application of force. The future of the BRP Sierra Madre remains uncertain, as China may seek to intensify gray-zone pressure while stopping short of actions that would provoke wider conflict. For the Philippines, maintaining resolve amid this uncertainty requires patience, strategic discipline, and a willingness to accept calculated risk without surrendering legal and political ground. As long as the Sierra Madre remains supplied and crewed, Ayungin Shoal will continue to stand as a living symbol of this contest, one in which endurance, rather than escalation, is likely to determine who ultimately holds the line.
Suggested Readings
Congressional Research Service. (2024). China-Philippines tensions in the South China Sea. Retrieved April 24, 2024, from https://crsreports.congress.gov/
Council on Foreign Relations. (n.d.). China’s maritime disputes: 1897-2023. Retrieved April 24, 2024, from https://www.cfr.org/timeline/chinas-maritime-disputes
Panda, A., & Putz, C. (2023). South China Sea flashpoints: The second Thomas Shoal crisis. The Diplomat. Retrieved April 24, 2024, from https://thediplomat.com/2023/11/south-china-sea-flashpoints-the-second-thomas-shoal-crisis/
