TOKYO - Japan and China, eager to nurture their fragile reconciliation, prepared on Wednesday for a summit aimed at setting aside rancour over the past and focusing on ways to tame rivalry over energy and influence.

Japanese Prime Minister Shinzo Abe, whose October visit to Beijing was a diplomatic coup after years of tension, plays host to Chinese Premier Wen Jiabao for a three-day visit studded with agreements, speeches and photo-ops intended to show ties are continuing to mend.

It is the first visit by a Chinese premier to Japan since October 2000.

On Wednesday, Abe and Wen will hold a summit that may unveil cooperation in energy, environmental protection and developing a "strategic" framework to find more common ground.

Yet even as they cheered the thaw, voices on both sides warned that the two countries have much distrust to overcome before relations gain a steady footing.

"The biggest objective and fruit of Wen's visit is the fact that the premier is visiting Japan," said Ryosei Kokubun, an expert on China-Japan relations at Keio University.

"There is still some fragility to Japan-China relations, so just to continue mutual visits will have a meaning."

Since becoming prime minister, Abe has avoided the visits to the Tokyo war shrine made by his predecessor, Junichiro Koizumi, which so angered China and led it to reject bilateral summits during his 2001-2006 rule.

World War Two leaders convicted as war criminals are honoured at Yasukuni Shrine along with millions of war dead. Asian countries say the shrine symbolises the militarism that drove Japan to invade much of Asia, including China, in the 1930s and early 1940s.

Abe has declined to say whether he will visit the shrine while in office. In an interview last week, Wen pointedly pressed him not to go.

NO CERTAINTY

Analysts in both Japan and China say there is no certainty that Abe, under pressure from his core conservative supporters, can heal ties long fraught by history and present rivalry.

"The improvement in Chinese-Japanese ties cannot possibly be all smooth sailing. There are still many problems between them that need shared efforts," wrote Liu Jiangyong, an influential expert on Japan at Tsinghua University, in an official Chinese paper on Tuesday.

"It's quite likely that right-wing Japanese forces close to Taiwan will increase pressure on Prime Minister Abe and interfere in the upturn in relations," Liu wrote in the overseas edition of the People's Daily.

China says Japan is too supportive of Taiwan, for 50 years a Japanese colony up to 1945 and now an island that Beijing wants to accept reunification with the mainland.

Beijing and Tokyo are also at loggerheads over the boundary between their exclusive economic zones in the East China Sea, which holds potentially lucrative gas and oil reserves.

Negotiators from the two sides have met twice in past weeks, seeking progress in the dispute before Abe and Wen meet. But on Tuesday, a Japanese official played down hopes of a breakthrough.

"At this point in time I don't expect that all the issues will be resolved by Premier Wen's visit," Noriyuki Shikata, a deputy spokesman for Japan's Foreign Ministry, of the gas field talks.

The two East Asian powers are also suspicious of each other's military ambitions.

Japan says China is too secretive about its rapidly growing defence budget, which is being used to beef up naval forces and buy or make advanced weapons.

China is wary of Abe's plans to revise his country's 1947 pacifist constitution to make it easier to deploy military forces and work more closely with Japan's key ally, the United States.

Parliament's lower house is likely to adopt on Friday a bill setting out procedures for a referendum required to make changes to the constitution for the first time, Japanese media reported. This would increase the likelihood of an amendment in the current session of parliament, they said.