China on Nov. 23 set up an air defense identification zone (ADIZ) over a section of the East China Sea that includes Japan's Senkaku Islands, which China also claims. This act is a dangerous provocation to Japan and the United States since the ADIZ overlaps Japan's air zone and violates Japan's territorial right over the islands. Given this situation, the Japanese government had no choice but to strongly protest to China and demand that Beijing scrap its ADIZ.

First and foremost, China should stop its provocative acts concerning the Senkakus, including intrusions into Japanese territorial waters around the islands. But Japan, for its part, must deal with the situation in a cool-headed manner. Self-restraint on both sides is vital to avoid an accidental military clash.

The possibility cannot be ruled out that a Chinese military aircraft and a Japanese Air-Self Defense Force aircraft could come so close to each as to lead to an unanticipated military incident. In 2012, ASDF jet fighters scrambled 306 times against Chinese aircraft that entered Japan's air zone. On the day China set up its air zone, two Chinese reconnaissance planes entered Japan's air zone and one of them came as close as about 40 km to Japan's airspace over the Senkaku Islands. Tokyo and Beijing should immediately open a channel of defense dialogue and establish a hotline so any critical situations can be quickly defused.