TOKYO (THE YOMIURI SHIMBUN/ASIA NEWS NETWORK) - It is an act that needlessly raises tensions between Japan and China, and it cannot be ignored.
The government has announced that a submarine of the Chinese Navy entered the contiguous zone near the Senkaku Islands in Okinawa Prefecture. The submarine is said to have sailed in the zone for several hours.
This is the first Chinese submarine confirmed in the zone.
A Chinese naval frigate also entered the zone at the same time.
Navigation in Japan's contiguous zone by vessels and submarines of foreign militaries itself is allowed under international law. However, as China has unilaterally claimed its sovereignty over the Senkakus, its recent move is unacceptable from the viewpoint of security.
Vice Foreign Minister Shinsuke Sugiyama lodged a protest with Chinese Ambassador to Japan Cheng Yonghua, expressing grave concern over the move. That stands to reason.
The Chinese Defence Ministry firmly responded, saying vessels of the Self-Defense Forces (SDF) had entered China's contiguous zone, prompting the Chinese Navy to track and monitor the vessels.
The Senkaku Islands are an inherent territory of Japan and effectively controlled by the nation. China's claim is irrelevant.
It is certain that this move by the Chinese military has thrown cold water on efforts to improve Japan-China relations, which have seen steady progress since the autumn last year.
Prime Minister Shinzo Abe has proposed reciprocal visits by the two countries' leaders this year, which marks the 40th anniversary of the signing of the Japan-China Peace and Friendship Treaty. Chinese President Xi Jinping has expressed a positive view of the idea.
Some observers speculate that the Chinese military intended to test the detecting ability of Japan's escort ships and patrol aircraft, given that China's submarine performance has been enhanced in recent years. However, such an act only undermines trust in the Japan-China relationship and does not serve Beijing's interest.
China should refrain from provocative acts.
Japan is also urged to respond calmly.
Nevertheless, homeland defense needs a firm response. Chief Cabinet Secretary Yoshihide Suga stressed, "Japan stringently defends its land, territorial waters and airspace."
Chinese government ships have repeatedly made incursions into Japan's territorial waters near the Senkakus with a frequency of several times a month. In each case, the Japan Coast Guard (JCG) has urged the vessels to leave the waters. The Chinese military also has increased its activities in the waters.
It is vital for the SDF to closely cooperate with the JCG and other entities to take all possible measures in warning and surveillance operations.
If a Chinese military ship intrudes into Japan's territorial waters near the Senkakus, the Japanese government plans to issue an order to the SDF to undertake maritime security operations and dispatch vessels.
To prevent accidental clashes between the SDF and the Chinese military, concrete steps must be ensured.
Over a "maritime and aerial liaison mechanism" being considered by the Japanese and Chinese governments, "positive progress" is said to have been made during their talks last December. It is hoped that the two countries will agree on the mechanism and launch its operation early.
The Yomiuri Shimbun is a member of The Straits Times media partner Asia News Network, an alliance of 23 news media.