Historical materials indicate that the Diaoyu Islands and their adjacent islets are part of China's territory, experts said Wednesday.

Cross-Strait experts refuted Japan's so-called "occupation" and "Terra nullius" claims to the islands, as well as its effective control of the islands.

They made the remarks at an international symposium in Taipei that focused on issues related to the Diaoyu Islands.

"Although the Diaoyu Islands are uninhabitable, they are not Terra nullius," said Song Chengyou, director of the Research Institute for Northeast Asian Studies with Peking University.

Song added that the Diaoyu Islands and their affiliated islets have been an integral part of China's territory since the Ming Dynasty (1368-1644), and the islands were first discovered, named and owned by the Chinese. The sovereignty belongs to China.

Even the Japanese agree, he explained.

"Illustrated Outline of the Three Countries" (1875) by Sendai scholar Hayashi Shihei is the earliest piece of Japanese literature to mention the Diaoyu Islands. In the "Map of the Three Provinces" and "36 Islands of Ryukyu" included in the book, the islands are painted the same color as the Chinese mainland, indicating that the Diaoyu Islands were part of China at the time.

The main reason that Japan claims sovereignty of the islands is "occupation." However, "occupation" follows the premise that the islands are "Terra nullius," said Chen Chun-i, an international law expert with Taiwan's Chengchi University.

But the "Terra nullius" claim goes against historical materials, Chen added.

As for Japan's "prescription" claim of the sovereignty of the islands, Chen argued that the premise of the claim is admitting the islands are not "Terra nullius," which presents a paradox for Japan itself. Endi