BEIJING - A Japanese politician known for anti-China rhetoric has found himself back in the headlines with an announcement that the Tokyo metropolitan government would buy some islets of the Diaoyu Islands, which are incontrovertibly Chinese territory.

The provocative move by Tokyo governor Shintaro Ishihara is detrimental to China-Japan relations. If allowed to go ahead, such "purchase" would constitute grim violation of China's sovereign rights.

In a speech at the U.S. Heritage Foundation on Monday, Ishihara said he had approached for a deal the "private owner" of a small chain of uninhabited islets of the Diaoyu Islands, which are also claimed by Japan.

The hostile move, following his latest denial of the December 1937 Nanjing Massacre less than two months ago, came in defiance of the fact that the Diaoyu Islands have been an integral part of Chinese territory since ancient times and that China has indisputable sovereignty over them.

Observers believe that the motive behind Ishihara's move, taken at a time when the 40th anniversary of the normalization of China-Japan diplomatic ties is drawing near, is to generate publicity and gain political capital in Japan for his hawkish posture.

In other words, Ishihara is attempting to bolster his profile by sabotaging China-Japan ties.

China has repeatedly proclaimed its stance concerning the Diaoyu Islands and warned that any unilateral action taken by the Japanese side would be illegal and invalid.

The Chinese Foreign Ministry has said China would not hesitate to take any necessary measures to safeguard sovereignty over the Diaoyu Islands.

Given the complex and sensitive nature of the issue, upon which the general atmosphere of China-Japan relations hinge, Japanese politicians at both central and local levels perhaps should exercise caution in their remarks and should not take any provocative moves.

The friendly ties between China and Japan have been the result of painstaking efforts by generations of political leaders and the civil societies on both sides.

The only logical approach to keeping the hard-won friendship is to cherish it, not damage it.