
Next month, the International Court of Justice (ICJ) will deliver its verdict in the case of Cambodia and Thailand’s territorial dispute over the Preah Vihear temple. For several months, the court has been poring over a judgment it made on the same issue fifty years earlier. That judgment was partly based on interpretations of old treaties, old maps and other fragments pertaining to the temple’s 900-year history. The whole exercise, in other words, has been as much an historical investigation as it has been a legal process.

Since neither the Thais nor the Cambodians seem inclined to accept an unfavorable verdict, the ICJ’s decision will probably go down as just another moment in the temple’s long and contested history, rather than as the end of the story so far as the dispute goes. Even so, the matter may be nearer closure than some of Asia’s other most tortuous territorial arguments.

Here, The Diplomat reviews the history of five of them. Among the contradictory narratives and fluctuating fortunes, one thing, at least, is clear. When Asian leaders insist that their country’s claim to a contested territory is historically indisputable, they are never right.

1. Diaoyu/Senkaku Islands

China and Japan both claim the Diaoyu/Senkaku Islands, which are equidistant between Taiwan and the end of the Japanese Okinawa/Ryukyu island chain. They are, however, under Japanese control.

Enjoying this article? Click here to subscribe for full access. Just $5 a month.

Chinese navigators and fishermen had known about “the Fishing Islands” since the 15th century or earlier, and Qing-era Taiwan government documents indicate that the islands, though never settled by the Chinese, were loosely administered from Taiwan. China never claimed the nearby Ryukyus, but 17th-century Chinese sources suggest that China considered the Diaoyu islands to be separate from the Ryukyu chain, mentioning as they do a maritime boundary between them at a place called Black Water Trench (this trench is marked on modern maps). However, other sources assert that the islands were a part of the old Ryukyu Kingdom, and it seems the Okinawans knew about them, and fished their waters, even earlier than the Chinese.

By the 19th century, with Japan emerging as a regional power, we start seeing a clash between new and old ideas about power and sovereignty. Japan began exploring the Senkaku Islands in 1884 within a few years of annexing the previously independent Ryukyus, and then claimed them as sovereign territory in January 1895 on the grounds that they were unoccupied features (terra nullius) – not on the grounds that they were part of the Ryukyus. This approach ran counter to the older view that the islands, though unsettled, fell within the Chinese “sphere.” Japan is effectively arguing here that the war it was fighting with China at the time was completely coincidental to its annexation of the islands. The Chinese government did not protest, but as a failing regime it may not have been in a position to do so. The Japanese only now created the name “Senkaku” for the islands.

However, Meiji-era documents suggest that Japan took control of the Senkakus opportunistically during the Sino-Japanese war, and not because it had spent a long time surveying the islands (as Tokyo later claimed) and found them to be empty. This is important because the Cairo Declaration of 1943 ordained that Japan should return territories taken from China as the spoils of war – something Japan formally agreed to do when it signed the 1951 San Francisco Peace Treaty. However, Tokyo has always argued that it assumed ownership of the Senkaku Islands as terra nullius before the signing of the Treaty of Shimonoseki in 1895, under which it annexed Taiwan and other territories, and that it is therefore permitted to hang onto the Senkakus because they were not spoils of war.


After World War II, the United States administered the Senkakus as part of the Okinawa/Ryukyu chain (though Taipei soon protested that the Chinese side had not realized the Diaoyu Islands were the same as the “Senkaku Islands”). Okinawa, and with it the Senkakus, then reverted to Japan in 1972, although the U.S. has never formally recognized Japanese sovereignty over the Senkakus.

Chinese references to the islands from this period arguably lend weight to the view that China no longer claimed them, with an official document referring to them as the Senkakus, and a People’s Daily report lumping them together with the Ryukyus in an article protesting U.S. occupation. Beijing dismisses these references as errors and insists that it claimed the Diaoyu Islands all along, while Tokyo argues that the Chinese cynically constructed their claim in the early 1970s following the discovery of nearby oil.

Tentative conclusions: History puts the Japanese claim under pressure. The crux is whether Japan is justified in claiming that it took over the islands as terra nullius in 1895, or whether China is right to argue that Japan annexed an existing Chinese possession as spoils of war.

Diplomat Brief Weekly Newsletter N Get first-read access to major articles yet to be released, as well as links to thought-provoking commentaries and in-depth articles from our Asia-Pacific correspondents. Subscribe Newsletter

2. Kuril Islands/Northern Territories

The Kuril Islands stretch between northern Japan and the southern tip of Russia’s Kamchatka Peninsula. They are commonly described in three groups – Northern, Central and Southern – all of which are under Russian control. Japan claims only the four islands of the Southern Kurils (which it refers to as the Northern Territories).

Enjoying this article? Click here to subscribe for full access. Just $5 a month.

Both Japan, working up from the south, and Russia, working down from the north, began seriously exploring the island chain in the 18th century. Japan took formal control of the four Southern Kuril islands in 1799, while Russia assumed control of the Northern and Central Kuril islands in 1821. The key moment formalizing this arrangement came with the signing of the Treaty of Shimoda in 1855, when Japan and Russia set their national boundary between the islands of Etorofu and Urup (i.e. between the Southern and Central islands groups).

But Japan then changed the status quo, assuming control over all three island groups during its period of late 19th century expansionism. This situation was then reversed when the Soviet Union took over the entire chain at the end of World War II – having declared war on Japan just days before Tokyo’s surrender.

While the San Francisco Treaty of 1951 specifically mentioned that Japan renounced its claim to the Kuril Islands, this is problematic as regards the Southern group because the Soviet Union never signed the treaty (meaning that Japan and Russia are even now formally at war); and Japan denies that it ever meant “the Kuril Islands” to include the four islands constituting the Northern Territories, which it says it has claimed throughout.


Russia has offered to return the two smallest and southernmost of the four islands to Japan as a way of resolving the dispute, but Japan has rejected this solution.

Tentative conclusions: Russia’s historical claim to the Southern Kurils is weak, just as its annexation of the islands in 1945 was opportunistic. However, it could be argued that Japan was the first to tear up the 1855 treaty establishing a settled Russo-Japanese border in the Kurils, and that its own aggressive actions rendered that border obsolete.

3. Arunachal Pradesh/South Tibet

The dispute over the northeastern Indian state of Arunachal Pradesh, which China claims as South Tibet, is particularly complex since it rests largely on the interpretation of two colonial legacies: that of Britain as the colonizer of India, and that of China as the colonizer of Tibet.

After British forces had invaded Tibet from their base in India at the start of the 20th century, the 1914 Simla Accord fixed a permanent border – known as the McMahon Line – between the two territories. The Tibetan and British representatives were in agreement about the line, but the Chinese representative did not sign the deal, and China has never formally recognized the border.

But was the Tibetan border even China’s to demarcate? Much of the discussion at the Simla Conference centered on whether China rightfully claimed suzerainty over Tibet, which had de facto independence at the time. The Accord set out that Tibet was part of China (even the Tibetans themselves accepted this during the talks), but added that “Outer Tibet” – effectively what is now the Chinese province of Tibet – was fully autonomous and would not have any Chinese officials within its borders. In any case, China refused to sign the Simla Accord, and so cannot fall back on the document in asserting its claim.

Instead, China’s claim to Tibet is more ancient – and arguably more tenuous. Tibet first fell within the sphere of Genghis Khan and the Mongol Yuan Dynasty (which some say wasn’t really Chinese at all), and thereafter moved in and out of China’s control, as the relative power of the two neighbors waxed and waned.

However, arguments about China’s claim to Tibet have relatively little bearing on China’s territorial dispute with India, since India recognizes Tibet as a Chinese province. What matters is whether India is right to insist that the British-imposed McMahon line should stand, even though China has never recognized it.

Newly independent India was understandably uncomfortable with the colonial-era Simla Accord, and supplanted it by signing a new treaty with China – the Panchsheel Agreement – in 1954. However, the deal did not address border issues, and Prime Minister Jawaharlal Nehru stuck with the McMahon Line despite abandoning other elements of the old colonial framework.

Some landmarks which are obviously Tibetan in character but which ended up on the Indian side of the line suggests that the Tibetan representatives at Simla – who were negotiating from a position of weakness – may have ceded rather too much territory to the British. The best example is Tawang, the birthplace of a 16th century Dalai Lama at Arunachal Pradesh’s western edge – a site on which China largely bases its claim.


Enjoying this article? Click here to subscribe for full access. Just $5 a month.

Had Arunachal Pradesh been the only disputed area along the Sino-Indian border, then it might have been easier to settle, since the McMahon Line served both Chinese and Indian purposes in terms of protecting their main strategic interests. Crucially, Premier Zhou Enlai wrote to Nehru in 1959 offering to “take a more or less realistic attitude towards the McMahon Line.” In other words, China could probably accept it if other territorial conditions were met. However, by pressing India’s claims in other areas, such as Aksai Chin, where China’s claim appeared stronger, Nehru bound Arunachal Pradesh together with those other contested areas, over which China and India eventually went to war in 1962 – after which neither side has felt able to back down.

Tentative conclusions: No formal border existed between India and Tibet before the McMahon Line, and though it was a primarily British creation, both the Tibetans and the Indians appeared to view it more or less as the “natural” border – with the exception of places like Tawang. So China’s claim, latterly based on anomalies like Tawang, appears weak. Zhou Enlai implied that China would have ceded Arunachal Pradesh to India, if India had been more flexible over other disputed areas – but that window of opportunity has long since closed.

4. Dokdo/Takeshima islands

Roughly equidistant between the Korean peninsula and the main Japanese island of Honshu, the islands lie closest to the small Korean island of Ulleung, and are now under South Korean control.

The Koreans claim that Dokdo has been theirs for 1,500 years, when a Korean king ordered the incorporation of Ulleung and Usando (the old name for Dokdo). The islands are marked on 16th century Korean maps.

Japanese maps from the 18th century paint a contrasting picture, since they include the islands within Japan’s Shimane Prefecture. However, a Japanese official document from a century earlier mentions Takeshima as falling beyond the limit of Japanese territory. Japan’s claim to historic ownership is certainly undermined by the fact that Tokyo formally annexed Takeshima in 1905 on the basis that it was terra nullius, before going on to annex Korea itself in 1910. At the time the Koreans did not object, although Seoul has subsequently argued that it had been in too weak a position to stand up to the Japanese.

After World War II, control of the Dokdo islands was handed back to South Korea. However, as with the Senkaku Islands, Japan claims that it was not bound to return Takeshima under the terms of the San Francisco Peace Treaty since it had not taken the islands as the spoils of war, but rather had annexed them as empty geographical features. Japan has always appeared confident on this point, repeatedly offering to take the case to the ICJ – a course it has never been open to where the Senkakus are concerned. The Koreans have subsequently argued that since the Korean War was raging at the time, they were too preoccupied to notice that Dodko was not expressly mentioned in the San Francisco Peace Treaty.

Tentative conclusions: Japan’s claim is undermined by the fact that it took over Takeshima at a time of significant relative strength over Korea, which had long regarded Dokdo as a Korean possession and not as terra nullius. But if the Koreans have such a strong case, it is strange that they don’t accept Japan’s repeated offer of international arbitration.

5. South China Sea

China claims about 90 percent of the South China Sea, and since 1947-1948 it has drawn a dotted line, now known as the “nine-dashed line,” on maps of the region to mark out its territorial claim. Its purpose was to clarify China’s claims and remove inconsistencies in older maps.

There is little doubt that Chinese fishermen and navigators have been familiar with the South China Sea’s geographical features for centuries: references to Scarborough Shoal, over which China is involved in a dispute with the Philippines, started appearing in official documents 2,000 years ago, and it appears on 13th century Chinese maps. However, China’s claim to such territories on the basis that they are “traditional fishing grounds” is problematic, since these waters have also been fished for centuries by people from the other littoral states.

Enjoying this article? Click here to subscribe for full access. Just $5 a month.

The nine-dashed line is also a shaky concept: China suddenly began using it in 1948 without explaining its origin or even defining its position, and there have been quiet admissions that it has no historical basis. The other South China Sea claimants reject its legitimacy, although their failure to complain about the line until relatively recently arguably undermines their staunch opposition to it today.

Some South China Sea features were formally recognized as belonging to the Republic of China government on Taiwan in 1952, when Japan ceded the Paracel and Spratly Islands to Taiwan via the Treaty of Taipei (this was a bilateral agreement to which other claimants, like the Philippines and Vietnam, were never party). The claims of China and Taiwan effectively overlap. However, Beijing bases its claim to these features on the nine-dashed line, not the Treaty of Taipei.

In any case, the Philippines does not recognize Scarborough Shoal as part of the Spratly Islands, although it does claim some of the Spratlys as the Kalayaan Group. The Philippine claim is arguably weakened by the fact that Manila only began to actively press its claim to the Shoal in 1997 – at which point it took ownership of the Shoal as terra nullius – and it does not feature on Philippine maps until then. However, Manila says it actually first claimed the Shoal in 1937-1938, but that it was unable to publicize this fact because of Japan’s incursions and subsequent invasion. China also made its first formal claim to Scarborough Shoal at around the same time, in 1935. Like the Philippines, it was under pressure from expansionist Japan, and Beijing and Manila were unaware that they were both preparing claims to the same geographical feature.

As for Vietnam, it claims both the Paracel (Hoang Sa) and Spratly (Truong Sa) island groups. The Vietnamese say that they have controlled the islands since “time immemorial,” but clear documentary evidence pointing to Vietnamese interest only begins in the 17th century. The European powers appeared to recognize that the islands were linked to Vietnam, and France, as the colonial power, launched a military expedition in 1933 to take control of the Spratly Islands after China had claimed them under the terms of the 1887 Sino-French Convention, which marked the boundary between China and Vietnam (though the location of the boundary was open to interpretation).

Vietnam’s claim to the islands was then complicated by the conflicting actions of the two rival governments which ran a divided country during the Vietnam War: while Communist North Vietnam recognized China’s claim to the islands, the South did not. However, soon after winning the war, the Communist government reversed its position and reasserted its territorial claim – a decision which culminated in the 1988 naval battle over the Spratly Islands between Chinese and Vietnamese forces.

Tentative conclusions: All historical claims appear shaky in a large area of sea that has served as a common fishing ground over the centuries. China’s nine-dashed line is historically very flimsy, but then Vietnam’s U-turn on ownership weakens its case, while the Philippines’ belated assertion of its claim to Scarborough Shoal undermines its position.