As Chinese Premier Wen Jiabao prepares to visit Japan the two nations have bathed their bruised ties in soothing rhetoric, but they remain far apart in the hard energy diplomacy that dogs their relationship.

Officials from the two nations meet in Beijing on Friday for more talks over disputed parts of the East China Sea, which holds oil and gas coveted by both energy-hungry countries.

Beijing and Tokyo disagree over the boundary between their exclusive economic zones in the sea, and Tokyo objects to Chinese development of the Chunxiao gas field out of concern that it would drain Japanese resources.

The technical talks follow discussions in Tokyo last week, and the two sides hope to make partial progress that could be unveiled when Wen is in Tokyo next week, said Liu Jiangyong, an expert on China-Japan ties at Tsinghua University in Beijing.

But the territorial dispute distils deeper fears in both Beijing and Tokyo as they contend for resources and international influence, and few observers expect a quick fix.

"On the one hand, there's resurgent nationalism in Japan that makes it hard for them to give away anything," Mark Valencia, an expert on maritime politics in Asia based in Hawaii, told Reuters. "But on the other hand, there is a growingly desperate need on both sides for the oil and gas from this area."

TENSION OVER RESOURCES

China's state-controlled CNOOC Ltd. had been due to start production at the Chunxiao field in 2006 despite repeated Japanese calls not to.

CNOOC has declined to confirm whether production is under way, although a company official told Reuters in February that work was going according to plan.

As China's economy booms and consumes more resources, broader tensions over access to global oil and gas have generated distrust between the two economic powerhouses of Asia, said Zhu Feng, an international relations expert at Peking University.

"Both sides are clear that energy could be a fuse leading to confrontation," he said. "I'm more optimistic about cooperation than most, simply because the consequences of conflict would be too great."

Beijing and Tokyo have been patching up relations after years of estrangement over former Japanese Prime Minister Junichiro Koizumi's visits to the Yasukuni war shrine, which critics call a symbol of Japan's past military aggression.

Ties have warmed since Japanese Prime Minister Shinzo Abe took office last September and made his first trip abroad as leader an ice-breaking one to China. Wen has called his visit next week an "ice-thawing" journey.

In an interview on Wednesday, Wen repeated China's offer to jointly develop resources in the sea and to "strive for a solution acceptable to both sides".

But Beijing and Tokyo have put forward competing ideas of what joint development of the sea area entails, and any agreement over coming days is likely to be over principles and process for more talks, not a substantial breakthrough, said Valencia.