ON MAY 2, China moved an oil rig to within 17 nautical miles of the Paracel islands.
Vietnam is butting heads with China over this as both claim the islands, called Xisha in Chinese and Hoang Sa in Vietnamese. The waters around the Paracels may hold an oil and gas bonanza.
No other nations claim the Paracels, which are 180 nautical miles from China's Hainan island and 156 nautical miles from Vietnam's coastline.
The rig placement triggered anti-China riots in Vietnam, leaving at least two Chinese citizens killed, dozens injured, hundreds of Chinese-owned factories looted and thousands of Chinese nationals evacuated. For days, Hanoi was unable to quell the riots.
Meanwhile, both sides blame each other for more than 1,400 boat ramming incidents around the rig.
As Singapore's Foreign Minister K. Shanmugam noted recently, the international media has painted China as a "big bully". But who the bully is depends on who owns the islands.
China claims that its sovereignty over the islands dates back to the East Han Dynasty (25-220 AD) By contrast, Vietnam says that, in the 17th century, when it occupied them, the Paracels were terra nullius - land that no state has ever ruled over or that which has been irrevocably abandoned by its prior sovereign.
Who is right?
While hoary historical details can be contested, official records from the last 130 years are clearer.
Even if the Paracels were terra nullius in the 17th century, China could argue that Vietnam failed to maintain continuous, peaceful sovereignty over them as required under international law.
For instance, on June 6, 1909, Admiral Li Zhun of the Guangdong Fleet was sent to tour the Paracels. With over 170 sailors in three warships named Fubo, Guangin and Shenhang, he inspected 14 islands, erected stone tablets engraved with each island's name, raised China's flag and fired cannons to declare the islands "sacred territory of China", according to official Qing records.
Yet France, which colonised Vietnam from 1884 to 1954, and thus represented it in foreign affairs, did not protest in 1909 as required under international law.
Law professor Nguyen Hong Thao of Vietnam National University in Hanoi argues that Admiral Li's actions were merely provincial-level ones, not ordered by China's central government and thus quite unworthy of protest.
It was following its victory in the Sino-French War (1884-1885) that France seized Vietnam. In their 1887 peace treaty, France ceded to Qing China any historic rights to the Paracels that Vietnam might have had. The treaty stipulated that all territory to the east of the 108° 03' 13" meridian - which included the Paracels - "are also allocated to China".
Thus when French troops occupied nine islands in 1930 and 1932 as terra nullius, including three in the Paracels, the Republic of China (ROC) - which had supplanted the Qing in 1912 - protested. The French soldiers were, in fact, accosted by Chinese islanders there.
Moreover, the ROC diplomatic mission in Paris issued an official note on Sept 29, 1932, asserting: "The Amphitrite Group and the Crescent Group constitute part of Chinese territory." (These are the respective names of the eastern and western island groups that make up the Paracels.)
Professor Nguyen argues that France did ask the ROC to submit that claim to international jurisdiction but China refused to do so.
After World War II, in the 1943 Cairo Proclamation and also in the 1945 Potsdam Proclamation that stripped a vanquished Japan of all its Pacific islands, the ROC recovered the Paracels and the Spratlys, an adjacent archipelago.
On Dec 12, 1946, the ROC sent four warships - Taiping, Yung- Hsing, Chun-Jian and Chung-Yeh - to the archipelagoes with 13 officials, who raised commemorative stone tablets on the islands. France did not protest.
In 1947, the ROC put all the islands administratively under Hainan. A map depicting that claim was officially circulated. Again, France did not protest.
In the 1949 civil war on the mainland, Mao Zedong's Communist forces drove out Chiang Kai Shek's Nationalists, who fled to Taiwan and regrouped as the ROC. On the mainland, the People's Republic of China (PRC) was established, which would contend with the ROC based in Taiwan.
WHAT is Vietnam's strongest claim? At the 1951 San Francisco Treaty of Peace, Japan officially renounced all claims to any Chinese territory it had grabbed, including the islands.
Vietnam notes that, when a vote was called for the return of the Paracels and Spratlys to China, 46 nations rejected it, with only three in favour and one abstention. Acceptance of sovereignty by other nations is important under international law.
But neither the PRC nor the ROC had been invited to this conference as the Allies could not agree which Chinese government was legitimate. That is, China was not there to make its case.
Still, the Soviet delegation, as proxy for Beijing, argued that both archipelagoes were "indispensable parts of China".
In 1950, PRC forces occupied the eastern part of the Paracels while the western part was seized by Saigon forces in 1954. It was only in 1974 that the Saigon forces were evicted by China to establish control over the whole archipelago. The next year, Saigon fell to Hanoi. When the French withdrew in 1954, two Vietnams were created by partition, one ruled from Hanoi in the north and the other from Saigon in the south.
WHAT, in turn, is China's strongest claim? In 1958, North Vietnam premier Pham Van Dong wrote an official letter to PRC premier Zhou Enlai arguably acknowledging China's sovereignty over the islands.
That letter, dated Sept 14, 1958, stated that his country "recognised and supported" the official PRC declaration on Sept 4, 1958 of its territorial seas of 12 nmi. In the declaration, China asserted that "this provision applies to all territories of the PRC, including... the Xisha (Paracel) islands... and all other islands belonging to China".
Shanghai Jiao Tong University law professor Xue Guifang feels that Pham's letter proves Hanoi's recognition of China's ownership of the Paracels. Notably, it expressed no caveat against the PRC claim to the islands.
In March 1959, the PRC set up the "Office of Xisha, Nansha and Zhongha Islands" on the biggest Paracel island, which none of the Vietnams protested against.
But when the United States delineated its Indochina theatre of war in 1965 to include the Paracels, China did not object, says Prof Nguyen, whereas Hanoi did. Yet in so doing, Hanoi referred to that zone as including "the Xisha maritime area of China".
Hanoi now argues that it had no say over the islands in 1958 as they were then under Saigon's control. Hence, premier Pham's letter was null and void.
And the letter must also be read in the context of the period, argues Hanoi's official 1988 "White Book" on the Paracels and Spratlys. This was when, it says, Hanoi and Beijing were "comrades and brothers... as close as lips to teeth", contending together with a mutual enemy, the US.
It also says that when Hanoi described the Paracels as "Xisha... of China" in 1965, it hoped Beijing would defend the islands from a US attack. It argues: "Vietnam trusted China... and believed that after the war all territorial problems would be suitably resolved".
With valid arguments on both sides, compromise seems unlikely for now and tensions will likely rise. When the jingoism has cooled down on both sides, perhaps they could negotiate and agree on some way to jointly develop the hydrocarbon resources in the Paracels.