In a speech delivered at the Center for Strategic and International Studies during her recent visit to the United States, Japanese Defense Minister Tomomi Inada said Japan will increase its engagement in the South China Sea by jointly patrolling the waters with the US.

Inada's statement has once again put the so-called joint patrols in the South China Sea in public spotlight. A senior US navy official first talked about such patrols in Malaysia in March 2015, sparking intense debates in Japan, Australia and Singapore. Compared with the members of the Association of Southeast Asian Nations whose response has been lukewarm, the proposal has gained the support of some Japanese given the fanned-up prevalence of the "China's threat" theory in Japan.

As the anti-China wave following an arbitration tribunal's ruling on China's disputes with the Philippines in the South China Sea subsides, China's joint efforts with ASEAN to resolve the South China Sea issue has made significant progress and the security situation in the waters has begun evolving to the region's advantage. These developments are in total contrast to the tension-building attempts of the US and Japan to pressure China through multilateral channels. Inada's latest "joint patrol" remark demonstrates that Japan has not abandoned its attempt to intervene in the South China Sea issue.

China and Japan are plagued by some structural contradictions, with Japan regarding China as an imaginary enemy whose rise should be checked. With such a mindset, Tokyo has been actively coordinating with Washington to implement the latter's "pivot to Asia" strategy and contain Beijing. And it seems both Tokyo and Washington believe the South China Sea is critical to the success of their conspiracy.

However, domestic oppositions as well as Inada's immediate ambiguity mean the plan for "joint patrols" with the US might remain a pipe dream.