VIENNA, Oct. 6 (Xinhua) -- Diaoyu Dao and its affiliated islands have been Chinese territory since ancient times and China's claim to their sovereignty is legal and reasonable, says an Austrian expert on international law.
China's claim is based on international law and is strongly substantiated by the results of abundant historical research, Gerd Kaminski, a professor of international law at the University of Vienna, told Xinhua in a recent interview.
Historical literature showed that China placed Diaoyu Dao under its coastal defense at the latest from the 16th century, said Kaminski, who is also a senior researcher on China and Southeast Asia studies.
Travel records of missionaries in China and Ryukyu from about 300 years ago also indicated that Diaoyu islands were regarded as Chinese territory, he added.
The Japanese government did not publicly claim the sovereignty over Diaoyu islands before the late Qing Dynasty, and it grabbed the islands after the Qing court was defeated in the Sino-Japanese War of 1894-1895, he said.
At the end of World War II, the Cairo Declaration demanded that Japan must return all the territories it had stolen from the Chinese, and the principle was reiterated in the Potsdam Proclamation, he added.
The expert also pointed out that the U.S.-Japan Treaty of Peace, commonly known as the Treaty of San Francisco, was vague on the question of Diaoyu islands.
Driven by its self-interest, especially economic interest, Japan has been intensifying its control over the islands after World War II by publicly claiming the sovereignty over the islands and driving out Chinese fishermen, he said, noting that there were reports of Japanese attempts to eliminate traces left by the Chinese on Diaoyu islands.
Commenting on Japan's recent "purchase" of Diaoyu islands, he said that the move is ridiculous, because even if the so-called island owner sold the islets, he had no right to change their sovereignty.
Both from the historical and legal perspectives, the Diaoyu islands belong to China, and China has never wavered on that issue, said Kaminski.