If Japan's policy is truly "to turn a sea of confrontation into a sea of co-operation", as its prime minister Junichiro Koizumi said yesterday, then his government's decision to authorise the start of gas drilling in the waters of the East China Sea disputed between Japan and China is not the best way to go about it.
The timing could not be worse. It comes a few days after the worst outbreak of anti-Japanese protests in Beijing since the two countries normalised relations in 1972. It concerns the heated subject of neo-nationalist Japanese textbooks which deny its imperial atrocities. Japan's trade minister called China a "scary country" after these events, while Chinese prime minister Wen Jiabao told reporters Japan must "face up to history squarely".
He went on to spell out a warning about Japan's ambition to secure a permanent seat on the United Nations Security Council: "Only a country that respects history, takes responsibility for past history and and wins over the trust of the people in Asia and the world at large can take greater responsibility in the international community". The point, it should be added, applies equally to China.
These are serious statements by the Chinese leadership, revealing how much their relations with Japan have deteriorated. They cast a shadow over the weekend visit to Beijing by Japanese foreign minister Nobutaka Machimura, which is intended to prepare the way for a visit by Mr Koizumi.
The gas exploration issue is part of a wider competition for energy resources between China, Japan and South Korea, fanned in turn by major shifts in the region's balance of strategic and political power.
On Tuesday a Chinese official warned against making the decision about gas exploration now, saying it would "fundamentally change the issue". Already worries are being expressed about the security of Japan's huge investment in China involving 16,000 businesses, its burgeoning trade there which now surpasses that with the United States and the safety of the three million Japanese tourists who went there last year.
This crisis has crept up gradually but now needs urgent attention from all the region's leaders before it is further exacerbated with quite unpredictable political and economic effects.
China and Japan are the second and third largest oil and gas consumers in the world. Thus there will be worldwide consequences if the East China Sea does indeed become a zone of confrontation, not co-operation. This regrettable decision could drive it that way.