Still a nuclear weapon also requires delivery technologies and systems. Since the end of World War II, Japan has attached great importance to developing aerospace technologies and solid-fuel rockets. Japan already has highly advanced solid-fuel launch vehicles and has already accumulated the technical data needed for developing intercontinental ballistic missiles. In theory, its H-II rocket, the satellite launch system, can be rebuilt into a ballistic missile to deliver nuclear weapons.

Now let's take another look at Japanese politics, which plays a key role in formulating the nation's nuclear policies. In recent years, the Japanese political circle has shown an increasing inclination toward right-wing conservatism. Driven by this, the military circle has undergone some changes. First and foremost is the higher administrative status of the military bodies. Japan's Defense Agency, established in 1954, was upgraded to the status of a full ministry in 2007, and the Abe administration is seeking to upgrade the Self-Defense Forces to a full-scale national defense force. Besides, the ruling party intends to ease the self-imposed ban on weapon exports that has been in place since 1967 to boost the country's defense influence, and furthermore, Tokyo has gone beyond the concept of "static" defense within its own territory to adopt so-called dynamic defense, which allows SDF units to be dispatched abroad and military bases to be set up overseas.

Given the inconsistency in its defense policy, it is not much a surprise that Tokyo maintains an ambiguous position over nuclear weapons. The Three Non-Nuclear Principles, namely that Japan should neither possess nor manufacture nuclear weapons, nor shall it permit their introduction into Japanese territory, were first outlined in 1967 by then Japanese prime minister Eisaku Sato, but when visiting the US in 1969, Sato signed a secret agreement with then US president Richard Nixon, which allows the US to bring nuclear weapons into Japan in violation of the tenets.

Japan also refused to sign a joint statement during the conference on the non-proliferation of nuclear weapons in Geneva, Switzerland, in April 2013, despite being the only country that has ever been the victim of atomic bombs.

Today, right-wing politicians, such as Shintaro Ishihara, are the most outspoken advocates of building nuclear weapons to counter threats from China and the Democratic People's Republic of Korea, but such opinions have invited less strong criticism from the Japanese society than before.

Obviously, Japan has met the three "physical" requirements for making and delivering nuclear weapons, and the determinant for it to become a nuclear-weapon state falls upon the country's nuclear policymaking. What is disturbing is its ongoing campaign to peddle itself as an advocate of nuclear arsenal reduction threatened by a belligerent neighbor.

By doing so, Tokyo is seeking to mislead international opinion, and by playing up a threat from China, alter its status as a non-nuclear weapon state. This should be a good reason for the international community to raise its guard.

The author is a researcher with the Institute of Japan Studies, Nankai University.