China's historical claims were re-emphasised on Tuesday in a 5,200-word white paper released by the State Council Information Office, which insists that "the islands are China's inherent territory in all historical, geographical and legal terms. No matter what unilateral step Japan takes over the Diaoyu Islands, it will not change the fact that the Diaoyu Islands belong to China".

According to the white paper, the earliest historical record of the islands can be dated back to the Ming dynasty (1368-1644), when they were mentioned in a book entitled , published in 1403, which refers to "Diaoyu islet" and to "Chiwei islet", another island in the Diaoyu archipelago.

During nearly 500 years, from 1372 to 1866, the imperial courts of the Ming and Qing (1644-1911) dynasties sent imperial envoys to the Ryukyu Islands 24 times to confer titles on the Ryukyu king, travelling past the Diaoyus en route. In 1609, Japan invaded and occupied the Ryukyu kingdom, claiming the entire string of islands to this day.

The white paper also says that fishermen from Taiwan and Fujian and other provinces have fished and collected herbs around the Diaoyus since ancient times and that, geologically, the islands are attached to Taiwan. The waters around the islands are 100 to 150 metres deep and there is a 2,000-metre-deep oceanic trench between the islands and Japan's Ryukyu chain.

In terms of international law, Beijing argues that Japan only formally claimed the Diaoyu Islands in 1895, incorporating them into Okinawa prefecture after it won the Sino-Japanese war and signed the Treaty of Shimonoseki, which China has long denounced as illegal and invalid.

The white paper says the islands "should be returned to China in accordance with such international legal documents as the Cairo Declaration [of November 1943] and the Potsdam Proclamation" [July 1945], which stated, among other things, the terms of surrender for Japan at the end of the second world war. Beijing also rejects the US trusteeship of the islands in the 1950s and the "return" of the "power of administration" over the islands to Japan in the 1970s.

Japan's claims are largely summed up by official documents which include surveys of the islands first conducted in 1885. These confirm, says Tokyo, that the islands were uninhabited and showed no trace of having been under the control of China. Based on these surveys, the Japanese government erected a marker on the islands to formally incorporate them into the territory of Japan.

Since then, Tokyo argues, the islands have remained an integral part of what it calls the Nansei Shoto Islands, as it calls the Ryukyu islands, which are the territory of Japan. The Diaoyus are neither part of Taiwan nor part of the Pescadores Islands in the Taiwan Strait, which Beijing calls the Penghu Islands and which were ceded to Japan by the Qing dynasty in accordance with the Treaty of Shimonoseki.

As a result, the Diaoyus, or Senkakus, were not included in the Treaty of Peace with Japan, signed by 48 nations - excluding China, then emerging from a civil war between the Nationalists and Communists - in San Francisco in September 1951. It came into force in April the following year. Under the treaty, Japan renounced its claims to territories it had occupied, while the Senkakus were placed under the administration of the United States as part of the Nansei Shoto (Ryukyu) islands. These then reverted to Japan in accordance with an agreement signed in June 1971.

The fact that China did not object to the Diaoyus being under the administration of the United States through the San Francisco peace treaty, according to Tokyo, "clearly indicates that China did not consider the Senkaku Islands as part of Taiwan". It also argues that it was not until the latter half of 1970, when the question of developing petroleum resources on the continental shelf of the East China Sea was first raised, that Beijing and Taiwan began to raise questions over the Diaoyus.

On questions of international law, Jia Yu , the deputy director of the China Institute for Marine Affairs, described as untenable Tokyo's two main arguments, of so-called - uninhabited land - and "acquisition by prescription" - a method of acquiring property by meeting statutory requirements of continuous possession.

" refers to land which has never been subject to the sovereignty of any state or over which any prior sovereign state has expressly or implicitly relinquished sovereignty," Jia told CCTV recently.

Noah Fangzhou Bian, a Chinese scholar with the faculty of law at McGill University in Montreal, Canada, said that from a view of international law and a precedent case involving the Island of Palmas - a landmark case which settled a dispute between the United States and the Netherlands over an island that now belongs to Indonesia - Tokyo's claim to have discovered the Senkakus alone does not give it legal title.

"In light of public international law, it can hardly be said that the Diaoyu Islands were when Japan placed its marker on the islands in 1895," Bian wrote in , a McGill journal. He said China had used the islands as a navigational aide and exploited its resources for centuries before Japan first laid its claim of .

American jurist Professor Hungdah Chiu and many researchers from the mainland and Taiwan as well as the Japanese historian Kiyoshi Inoue agree that the islands were ceded to Japan by China after the Sino-Japanese war in 1895. However, Inoue, an academic at Kyoto University, wrote 40 years ago: "Even though the islands were not wrested from China under a treaty, they were grabbed from it by stealth, without treaty or negotiations, taking advantage of victory in war."

In a PhD thesis published in the journal , Peking University scholar Wu Hui cited the application of "intertemporal law", by which "a juridicial fact must be appreciated in the light of the law contemporary with it," according to the Island of Palmas case, to argue that China had held a sovereign right to the islands since the 15th century.

Several Western scholars support Tokyo's argument of prescriptive acquisition, because of its long and effective control of the islands. Tokyo has claimed that the fact that for 75 years, from 1895 to 1970, China never raised any objections to Japan's territorial rights over the islands suggested China had given its tacit consent to the status quo.

But Gavan McCormack, an East Asian affairs expert and emeritus professor with the National University of Australia, said that China had been weak and in no position to resist Japan: "From 1895 to 1945, that is to say from the first to the second Japan-China war, China was in no position to contest Japan's claims."

Jia said: "The so-called acquisition by prescription of territory has been all along extremely disputable in international law. Those against it totally deny the legitimacy of prescription as a way to obtain territory."

Another crucial factor at play is how Washington views the dispute, as it occupied the islands before handing them to Tokyo in 1971. At the time, the US considered the disputed islands as part of the Ryukyu territory, and therefore theirs to administer as they wished. In June 1971, when Japan and the United States signed a pact to hand over Okinawa to Japan, the Diaoyus were included in the area to be handed over. It was also at this time that the mainland and Taiwan began to declare ownership.

At least one mainland academic suggests the US should be involved in settling the dispute, especially after Secretary of State Hillary Rodham Clinton indicated earlier this year that Washington was willing to play a role.

Professor Liu Ming , deputy director of the Shanghai Academy of Social Sciences' Institute of Asia-Pacific Studies, said Washington had a responsibility to help as it handed over the islands to Tokyo in 1972 after they had been under American trusteeship since 1945.

"In this context, Washington has a historic responsibility and thus a role in the issue, [provided that] Washington holds a neutral stance. When Clinton proposed the trilateral talks, she said the US had never taken a position on sovereignty."

Taiwanese President Ma Ying-jeou has suggested referring the issue to the International Court of Justice but Tokyo has shown no sign of backing down in the long-running feud and refuses to negotiate a settlement - officially, it even refuses to acknowledge that there is a territorial dispute.

Liu agrees with Ma's suggestion of referring the claim to international arbitration, and that the two sides shelve their claims for now, while allowing common fishing and the common development of resources of its adjacent areas.