US President Barack Obama recently declared that a 1960 defence treaty obligates his country to defend Japan if disputed islands in the East China Sea are attacked.
Called Diaoyu in Chinese or Senkaku in Japanese, the islands are "under Japan's administration", Mr Obama noted. It is their ownership that China, the potential attacker, disputes. Making up a total of under 7 sq km in area, the five uninhabited islets and three barren rocks lie slightly on Japan's side of the median in the East China Sea, about 120 nautical miles east of Fuzhou, China, 90 nautical miles north-east of Taiwan and 90 nautical miles from the Japanese Ryukyu islands.
Their value lies below, in "the most prolific oil and gas reservoirs in the world, possibly comparing favourably with the Persian Gulf area", according to a 1968 US Naval Oceanographic Office study. This study sparked the dispute, as whoever owns the islands owns the oil and gas.
Japan has been administering the islands since 1972, maintaining a lighthouse and patrolling the waters. China insists that Japan occupies the islands illegally.
Neither side has been willing to submit to international adjudication or arbitration. Both sides, having used the islands to stoke nationalist feelings, fear their citizens will not accept an adverse decision, which would undermine the ruling party's legitimacy.
For China, additionally, surrendering its claim to the islands would reflect badly on its claim to Taiwan as well. Now throw the United States into the mix and the islands could well become a flashpoint in North-east Asia.
For these reasons and because the world's three largest economies are involved, the dynamics in this dispute differ significantly from the one in the South China Sea. Here, two big sets of concerns - geophysical and treaty - matter the most.
THE East China Sea is a semi-enclosed body of water, just 345 nautical miles across at its widest point between China and Japan. A median line would give each state less than the 200 nautical miles exclusive economic zone (EEZ) permissible under the United Nations Convention on the Law of the Sea (Unclos). A coastal state has sovereign economic rights over the marine resources within its EEZ.
Associate Professor M. Taylor Fravel, a political scientist at the Massachusetts Institute of Technology, tells The Straits Times, however, that - although often used by claimant states - the median line concept is not found in the text of Unclos. In fact, Unclos has exacerbated matters as it also allows a coastal state to claim, alternatively, to extend its claim to the continental shelf up to 350 nautical miles with the proviso of revenue sharing in the area between 200 and 350 nautical miles from its shores, depending on where its continental shelf ends.
As such, China is claiming that its continental shelf ends at a deep trench in the seabed called the Okinawa Trough, which lies up to 77 nautical miles beyond the 200-nautical mile boundary (but does not exceed 350 nautical miles from its shores). The trough is 900 km long, 230 km at its widest and 2,700 metres at its deepest. It extends from the north of Taiwan to the south-west of Kyushu, Japan.
Shanghai Jiao Tong University law professor Julia Xue Guifang tells The Straits Times that the trough forms a natural boundary between China and Japan. China has offered ample geophysical evidence that there is indeed "a continuous, evenly extended landmass, a natural prolongation from its shores that terminates at the trough". This means the continental shelves of China and Japan are not connected.
Moreover, the trough was seen as a natural boundary between China and Japan even in ancient times. Professor Xue notes that 16th-century Chinese navigation records tell of sailors going to the Liuqiu Kingdom (Okinawa) to collect tribute. These ancient mariners noticed changes in the colour of the waters when sailing over the trough, when they would sacrifice live pigs and sheep to the sea god. This haishenji (ritual to the sea god) was also called guogouji (the trough-crossing ritual).
However, Japan counters that the whole sea is made up of the East China Sea Basin on the west and the Okinawa Trough on the east, whose total cross section is a distorted W, with the W's middle peak being an uplifted belt, upon which the islands sit.
This uplifted belt, Japan argues, is a natural prolongation of not just China's mainland but also the Ryukyu islands 90 nautical miles away, so the disputed islands are really a part of Japan's Ryukyu islands.
Under Unclos, when continental shelves of two coastal states are continuous, as Japan argues, no feature like the trough may serve as natural marker to separate their EEZs. If so, the median is the fairest and the islands would fall within Japan's side.
Yet, under Unclos, Prof Fravel notes: "China as a larger country would probably be entitled to a bit more than half of the EEZ."
PROF Xue points out that, before Japan seized the islands in 1895, Meiji Japan recognised Qing China's sovereignty over them. There are two Japanese maps of 1783 and 1785 indicating the islands as part of Fujien, China. The 1785 map, for example, was reproduced in a book published in Japan in 1785 called Sangoku Tsuuran Zasetsu (Illustrated Picture Of Communication Between Three Countries). Prof Xue also notes that among Japanese diplomatic papers is "a very important" 1885 letter from then Foreign Minister Inoue Kaoru. It cautions the Japanese Cabinet against "suddenly establishing publicly national boundary marks" on the islands. This might "easily invite Chinese suspicion (as) those islands are near the Chinese national boundary... there are Chinese names on them". So, 10 years before its land grab, Japan knew the islands were not terra nullius, or territory belonging to no sovereign, Prof Xue says.
Prof Fravel feels that "the letter does perhaps weaken part of Japan's claim, but it also does not indicate Chinese sovereignty and so is still somewhat ambiguous". Japan claims they were terra nullius when it annexed them three months before the First Sino-Japanese War (Aug 1, 1894 to April 17, 1895) ended.
As the losing party in that war, China had to sign away all seized territory to Japan under the 1895 Treaty of Shimonosek, including Taiwan "and its appurtenant islands"; the disputed islands are not specifically mentioned by name. The war saw China's military smashed, as the Qing dynasty collapsed and the country fell into 50 years of warlord chaos.
Later, Japan itself was defeated by the Allies in World War II. It was then required under the 1943 Cairo Declaration, the 1945 Potsdam Proclamation and the 1951 San Francisco Peace Treaty to return Taiwan "and its appurtenant islands" to China. (The US, as the occupying power in post-war Japan, held sole trusteeship of the disputed Senkaku/Diaoyu islands until 1972, when it turned over their administration to Japan).
Japan argues that the disputed islands stand apart from Taiwan "and its appurtenant islands" or, indeed, all other Chinese territory it annexed under the 1895 treaty.
Since the islands were terra nullius when annexed, they were legally independent of the other Chinese territories it seized. That is, the islands were legally incorporated into Japan as its own territory well before WWII. So the post- war settlements cannot require Japan to return these islands, only all other territories it seized from China.
Has China lost title?
SO IF China ever had title to the islands, it was probably inchoate, which may be lost under international law if another state occupies and exercises effective governmental authority over them.
International law favours such an occupying state while disfavouring a disputant state that has seemingly acquiesced to it for a long period.
Japan says it has demonstrated continuous, peaceful authority over the islands, which China (and Taiwan) did not contest for 76 years from 1895 until 1971, when China first filed a protest.
If it really felt that the islands should have reverted to it after WWII, why did China raise no protests at all until 1971? This suggests that, up to 1970, China did accept Japan's sovereignty over the islands. At the very least, China did not exercise continuous authority over them after 1895.
However, Prof Xue notes, China had no diplomatic relations with Japan until 1972. Further back, the 1940s and 1950s saw civil war and famines in China. With millions dying, diplomatic protests about land grabs were the least of China's priorities.
There is no settled international law as to how long apparent acquiescence must last for a state to lose title to disputed territory. So things have remained stalemated for over 42 years, with occasional clashes at sea.
Will war break out? Prof Fravel says: "War is unlikely. An accident could spark a real crisis, but I doubt a major war." Prof Xue concurs: "Leaders on both sides will wisely step back from any brink."
But as both sides abjure adjudication or arbitration, the status quo is likely to be maintained indefinitely. So both sides will continue patrolling the waters while respecting each other's presence in the area, Prof Xue thinks. It is also likely, she feels, that the hydrocarbon resources in the disputed zone will be jointly developed, as permitted under Unclos, without sovereignty being ceded.