Whose sovereignty over Xisha Islands?

Tensions between China and Vietnam over sovereignty issues in the South China Sea flared up again on May 2, 2014 when China positioned an oil rig in waters off the disputed Xisha Islands. Vietnam protested this action and sent vessels to disrupt the rig's operations. China responded by sending more ships to protect the rig. Inevitably with the numbers of opposing vessels in the area, a violent clash occurred on May 7 injuring some Vietnamese personnel and damaging some vessels.

Vietnam has launched a strong diplomatic and public relations campaign to support its position. It appears to be winning the public relations battle with much global commentary supporting its claim that the rig is illegal and painting the situation as yet another example of China's assertiveness. However, a closer look at the situation suggests that China may be within its rights with the rig. Undoubtedly, however, it could have handled the situation more diplomatically rather than acting unilaterally in a way that inevitably would lead to increased tension.

Locating the rig

The rig is about 120 nautical miles east of the Vietnamese coast, and 180 nautical miles south of China's Hainan Island. These are the two nearest mainland points from which an exclusive economic zone and continental shelf may unquestionably be measured. Equally importantly, however, the rig is about 14 nautical miles from a small island in the Xisha Islands claimed by China and 80 nautical miles from Yongxing Island, a large feature with an area of about 500 hectares occupied by China.

Yongxing Island is indisputably an island under the regime of islands in the 1982 UN Convention on the Law of the Sea and thus entitled to an EEZ and continental shelf. Despite global commentary that suggests otherwise, a negotiated maritime boundary in this area would likely place the rig within China's EEZ even if reduced weight was given to China's claimed insular features.

Vietnam claims that because the rig is closer to its mainland coast than to China's and well inside 200 nautical miles of its coast, it lies within its EEZ and on its continental shelf. Superficially this argument may appear attractive but geographical proximity alone is not an unequivocal basis for claiming sovereignty or sovereign rights. There are many examples around the world of countries having sovereignty over features well inside the EEZ of another, or of EEZ boundaries being established significantly closer to one country than to another.