Members of Japan's Self-Defence Forces' airborne troops stand at attention during the annual SDF troop review ceremony at Asaka Base in Asaka

China is on the march. Or, to be precise, China has made a strong push, militarily and otherwise, into seas nearby, setting off alarms among its neighbors. Now Japan has pushed back, announcing it will “reinterpret” its pacifist constitution so it can be more militarily aggressive in responding to China’s persistent territorial expansionism.

Japan’s actions, however, have also raised alarms. A century ago, Japan set out on a destructive path of conquest, and many still remember firsthand the brutality with which Japanese troops occupied the region — from Korea and the Philippines, through Manchuria and China, Vietnam and Thailand, all the way to Singapore. Though China is now threatening peace, the memory of Japan’s savage adventurism adds to the general unease.

If Japan’s prime minister, Shinzo Abe, is to persuade countries nearby that his intentions are honorable, there are actions he can take to show that Tokyo has learned the lessons of the past and truly reformed. If he does not, his latest political maneuver is likely to set his neighbors’ nerves on edge, adding to the prospect of warfare between two or more of the nations on the East and South China Seas.

Japan's PM Abe looks at a prompter as he speaks during a news conference to wrap up the ASEAN-Japan Commemorative Summit Meeting at his official residence in TokyoYou may have seen the photo of Chinese vessels pouring thousands of tons of sand onto a reef in the Scarborough Shoal in the South China Sea. It is perhaps the most startling evidence of how aggressively China is pursuing the resources it needs to maintain its extraordinary rate of economic growth. The creation of a new island out of a coral reef, on which it can build a strategically important air strip, shows how determined Beijing is to grab the land and raw materials it feels entitled to, whatever international law may say.

It is no surprise that the Philippines, which disputes ownership of the Scarborough Shoal, welcomes Abe’s abandonment of 60 years of pacifism. But other neighbors view Tokyo’s change of heart as more sinister. The South and North Koreans, at loggerheads since the end of the Korean War in 1953, share bitter memories of the Japanese occupation. They are less convinced that Abe’s first step toward a return to militarism is necessary.