China's air zone will weigh on Japan's defence policy revision

China's controversial declaration of an air defence identification zone is particularly ill-timed, given that Japan is expected to release before the end of the year a new revision of its core defence policy, the National Defence Programme Guidelines.

The first guidelines were introduced in 1976 and remained in place for 20 years, reflecting the static cold war security environment. It had a territorially based perspective, with the armed forces structured and equipped to defend Japan in concert with the US.

The 1995 revision was a post-cold war adjustment, beginning to unfetter Japan's Self-Defence Force from outright dependence on Washington and venturing into global governance through involvement in peacekeeping and disaster relief operations. The next revision, a decade later, sought to consolidate these trends.

An unsettled global security environment then prompted Tokyo to quicken the pace, with the revision period reduced to five years and new guidelines issued in 2010. This move was further encouraged by the Japan Defence Agency's elevation three years earlier to become a full ministry.

The 2010 revision included several refinements but most critically introduced a new concept known as the "dynamic defence force", along with the notion of "dynamic deterrence".

"This concept was developed precisely as a result of concerns over grey-zone crisis, which happens at a lower spectrum of intensity than traditional deterrence posture," Japanese security scholar Sugio Takahashi explained in a recent paper. "The dynamic deterrence concept … is geared towards challenges that cannot be easily assigned to one or the other of the two traditional categories of peacetime and wartime."

Such as the Senkaku/Diaoyu territorial dispute, with its brew of tensions.