US-Japan alliance and China

But as part of the security policy of the US for East Asia, Obama has defended Japan's ADIZ (Air Defense Identification Zone) and said he preferred that Japan use the Collective Self-Defense Right given the developments in Ukraine and the security situation in Asia.

Despite all this, the US sees both Japan and China as very important trade partners, but the two Asian powers are at odds with each other. And it's because of the dispute between Japan and China that the US has got the legitimacy of strengthening its presence in Asia.

The US wants to strengthen and widen its security zone against China, Russia and the DPRK. But more than anything else, the US wants its economy to fully recover by collaborating with China and other emerging countries in Asia. Japanese companies, too, believe that collaboration with China and other Asian economies will help the Japanese economy to recover.

In this age of globalization, the US does not believe in following a policy of containing China and Russia. But at the same time, it wants to strengthen its presence in Asia and build an alliance of the American, Japanese and Australian militaries as a counter-move against the Chinese military's modernization.

The US' multi-level strategy includes cyber-attacks. So, in case of an "emergency", the US will collaborate with Japan against Chinese-Russian cooperation, just like it used to do during the Cold War days. But Washington should avoid indulging in such power games because they don't benefit any country. The fact is that, if the China-Japan dispute spirals out of control, the US will protect only its own, rather than Japan's, interests.

The US has always followed the two-sided policy of using Japan against China, and vice-versa. And China and Japan have always viewed each other with skepticism, which has served the US' interests. The US believes that it can benefit only if Japan and China are at loggerheads.

But contrary to what Washington thinks, only a stable and friendly relationship among the US, Japan and China can serve the interests of all the three countries and establish lasting peace and prosperity in Asia.

Therefore, China and Japan should take measures to resolve their territorial dispute and strengthen their economic ties in order to optimize their mutual benefits.

A stable and friendly relationship among the US, Japan and China will help Asia become secure and prosperous.

And it's time the US took the lead in building such a triangular relationship.

The author is a professor of East Asian regional studies at Aoyama Gakuin University in Tokyo and a research fellow at Harvard University.