A member of the Japanese Diet recently submitted a letter of inquiry to the Japanese government inquiring whether local governments and local councilors in Japan have the legal obligation to observe Taiwan-related content in the 1972 China-Japan Joint Statement.

What makes the otherwise normal inquiry of a lawmaker an international concern is the Japanese government's reply. In a letter of reply to the inquiry, the Japanese government claimed that the 1972 China-Japan Joint Statement is "not legally binding".

That is tantamount to a covert encouragement to some Japanese local councilors' activities in Taiwan, which not only shakes the political foundation of Sino-Japanese diplomatic relations but also sends a wrong signal to the secessionists on the island.

As Chinese Foreign Ministry spokeswoman Mao Ning made clear, China firmly opposes official interaction in any form between Taiwan and countries having diplomatic ties with China. The one-China principle is the foundation for China-Japan relations.

The Japanese government recognizes that there is but one China in the world, Taiwan is an inalienable part of China, and the government of the People's Republic of China is the sole legal government representing the whole of China, as it explicitly acknowledged in the 1972 China-Japan Joint Statement. It pledges in the statement that "The Government of Japan fully understands and respects this position of the Government of the People's Republic of China, and it firmly maintains its position under Article 8 of the Potsdam Proclamation".

Article 8 of the Potsdam Proclamation unequivocally states that the "terms of the Cairo Declaration shall be carried out". And the 1943 Cairo Declaration explicitly demands that "all the territories Japan has stolen from the Chinese, such as Manchuria, Formosa, and the Pescadores, shall be restored" to China.

These documents not only confirm the fact that Taiwan belongs to China, but also constitute the legal basis for ending the state of war between the Allied Nations and Japan and building the postwar international order in the Asia-Pacific. They are certainly legally binding.

In 1978, the Chinese and Japanese governments signed the Treaty of Peace and Friendship Between China and Japan, in which the two sides affirmed that the China-Japan Joint Statement "constitutes the basis for relations of peace and friendship between the two countries and that the principles set out in that statement should be strictly observed". The treaty officially came into effect after deliberation and approval by the legislators of the two countries. It affirmed the principles and content of the joint statement in legal terms and is also legally binding.

Taiwan has thus been back under China's sovereign jurisdiction for 80 years. It is ridiculous that the Japanese side now tries to obscure historical facts regarding the Taiwan question, which severely misleads the Japanese people and violates the Japanese government's promise of adhering to the one-China principle.

The Japanese side should fulfill its relevant legal obligations, abide by the principles and spirit of the four political documents that are the basis for its relations with China, act prudently on the Taiwan question and honor its promise of adhering to the one-China principle with concrete actions.

- Li Yang, China Daily