Arguing Over Blocks: Do China and the Philippines Both Have a Claim?

By Greg Poling

[Editor’s note: This post is the first in a new blog series, The South China Sea Frame-by-Frame. It incorporates data and imagery from the CSIS Southeast Asia Program’s innovative policy tool, The South China Sea in High Resolution.]


National Library photo. Used with permission.

The Philippines opened yet another chapter in the ongoing South China Sea dispute with its neighbors on February 29, 2012 by inviting foreign companies to take part in its long awaited fourth Energy Contracting Round. This round opens bidding on 15 oil and gas blocks. Two blocks, Areas 3 and 4 near the Reed Bank, fall within China’s so-called “9 dash line” claim, which is mirrored by Taiwan. Beijing quickly responded to Manila’s announcement by lodging a formal protest, reiterating its “indisputable sovereignty” over the islands and waters of the South China Sea, and calling any oil exploration “unlawful.” Taiwan’s foreign ministry followed suit with a March 13 statement saying, “The Reed Bank is part of the Spratly islands . . . and we reject any claim or occupation by any means of the islands and the surrounding waters.”

What is clear in this instance is that China and Taiwan’s claim cannot rest on the “9 dash line” alone and be taken as legitimate. There is simply no basis in international law supporting that grandiose claim – a fact even Beijing seems to increasingly recognize, as evidenced by the much-analyzed Chinese Foreign Ministry statement earlier this year that the South China Sea dispute is about the “islands and adjacent waters,” not the sea in its entirety. The “islands” in this case are the Spratlys.

The question then is not whether Areas 3 and 4 lie within the “9 dash line,” but whether they fall within the adjacent waters of nearby islands claimed by China. This is the point made last month by Robert Beckman. Under the UN Convention on the Law of the Seas (UNCLOS), to which both China and the Philippines are signatories, a country’s islands generate an Exclusive Economic Zone (EEZ) out to 200 nautical miles in it has exclusive rights to all natural resources, including oil and gas.

The key word here is “islands,” as distinguished from rocks, shoals, banks, or other features. Under UNCLOS, an island must meet two criteria: it must remain above water at high tide, and it must be capable of sustaining human life and economic activity of its own. The latter requirement, habitability, is ambiguous; the former is not. Any feature that does not meet these requirements is eligible only for territorial waters out to 12 nautical miles, and there are no features within 12 nautical miles of the blocks in question. Nanshan Island and Flat Island are the closest Spratlys above water at high tide, though they are still twice as far as the Philippine coast is from the blocks.

As China and Taiwan would eagerly point out, much, though not all, of Areas 3 and 4 would fall within their hypothetical 200 nautical mile EEZs. While accepting both islands as habitable for the sake of argument, it is worth noting that neither has fresh water or significant vegetation, both are currently occupied by the Philippines, and the larger of the two, Nanshan, is only about 1000 feet across at its widest point.

Since the EEZs of Nanshan and Flat Islands overlap with that of the Philippines, being less than 200 nautical miles away, a compromise would need to be reached on their respective boundaries. Under UNCLOS, such a settlement can be reached bilaterally or through arbitration at one of several international forums, most importantly the International Tribunal on the Law of the Seas (ITLOS). Not only do these forums exist, but they have decades of precedent to rely upon. The starting point for any settlement on maritime boundaries under international law is almost always equidistance (there are other methods of arbitration such as the angle-bisector method that can apply in the case of adjacent coastlines, but would not make sense in the case of an island).


By delimiting the halfway point between Flat and Nanshan Islands, and the Philippine coast, it is possible to estimate with some accuracy where China’s best-case EEZ limits would fall. They are best-case because such a settlement would go against all prior precedent. As the recent ITLOS decision concerning Bangladesh and Myanmar reiterated, the most important consideration in delimiting maritime boundaries has traditionally been the principle of avoiding inequity – including by considering the relative length of relevant coastlines, and by taking into account any bays or other concavities that unduly influence the EEZ boundaries. This case would involve two islands with combined coasts of less than half a mile versus a Philippine coast of hundreds of miles – a clear inequity. In addition, the entire disputed portion of the blocks is a result of the concavity in the gap between the Philippine islands of Palawan and Mindoro – another inequity. Both of these facts would almost certainly result in shifting the equidistance line significantly toward the islands.

What this exercise reveals is that a sliver of two oil and gas blocks, roughly 250 square miles out of more than 4,700 square miles, or just over 5 percent, could conceivably be considered disputed under international law. And even that would require a remarkable deviation from prior legal precedent. For the time being, Manila might be better off taking the high road and removing the sliver in question from Areas 3 and 4 until an eventual settlement of EEZs is reached. That would let the Philippines appear magnanimous and greatly strengthen its claim to be the party following the law while ceding almost nothing.

Mr. Gregory Poling is a research assistant with the CSIS Southeast Asia Program.

Gregory Poling

Gregory Poling

Mr. Gregory B. Poling is director of the Asia Maritime Transparency Initiative and a fellow with the Southeast Asia Program at CSIS.