Robert Thomas, commander of the Seventh Fleet, said on Thursday that the US would welcome a Japanese extension of air patrols over the South China Sea, because "the Chinese fishing fleet, the Chinese coastguard and the [navy] overmatch their neighbors." It is rare that a top US navy officer openly called for Japan to counterbalance China in the South China Sea. By press time, there had not been an official response from either China or Japan. But, it's certain that China would be firmly against any extension of Japanese air patrols over the South China Sea. If Japan takes the plunge, it will have to face countermeasures from China.

Japan has expressed its interest in playing a role in the South China Sea, but we hope Tokyo could curb its appetite. Even if the South China Sea is of great significance to Japan as the sea passage for the island nation to the Middle East and Europe, this can't alter the fact that as an extra-regional country, Japan is not supposed to interfere in South China Sea disputes.

China has reiterated its support for free South China Sea navigation. There is no reason for Japan to expand air patrols into the region, altering the geopolitical landscape and acting like a protagonist. 

The US has maintained a military presence in the South China Sea. However, it doesn't have the final say in the waters. Washington has no authority to draw Japan in to intensify military competition.

Japan won't be allowed to enter the South China Sea as another US. The region won't be overshadowed by the US-Japan alliance. The support of only a few countries for Japan can never represent the stance of the whole region and China's attitude must be respected.

If Japan unilaterally sends air patrols into the South China Sea, it's imperative that China makes a counterstrike. China can announce the establishment of a South China Sea Air Defense Identification Zone and accelerate buildups in the South China Sea. It can also cement military cooperation with Russia in Northeast Asia as a counterweight to the US-Japan alliance.

The US incitement of Japanese military forces to enter into the South China Sea indicates that Washington is in need of more Japanese help in implementing its rebalancing strategy in the Asia-Pacific region. The entry of Japanese air forces into the South China Sea at the invitation of the US is equivalent to the entry of the US-Japan alliance, which should be viewed as an open provocation to China. The countermeasures taken by China should be unprecedentedly strong.

Tokyo has strengthened its efforts to guard against China's rise, but it shouldn't become hysterical. Making an enemy of China at any time is not in accordance with Japan's interests. Japan cannot afford it if the country wants to retread the militarist road. As two major powers in the Asia-Pacific, China and the US are developing a new type of major power relationship, which means the two won't easily come to a break. We hope Japan could stay sober.