SHANGHAI -- Wen Jiabao flies to Japan this week for the first visit by a Chinese premier in almost seven years, evidence ties are recovering after nearly collapsing over disputes about Japan's World War II aggression.

Expectations for the visit are mixed, yet the mere fact that Wen is going reflects a sharp turnaround in ties that began with an icebreaking visit to Beijing by Japanese Prime Minister Shinzo Abe last September.

"I feel strongly that my trip has a real mission," Wen told Japanese reporters in Beijing ahead of the three-day visit starting Wednesday. "Sino-Japanese relations are at a critical stage and both countries should make an effort to push forward ties."

Wen plans to address lawmakers and issue a joint statement with Abe expressing their "aspirations to build a strategic and mutually beneficial relationship." Military cooperation, economic dialogue, and collaboration on energy conservation, environmental protection and finance are also on the agenda.

In an attempt to emphasize the human side of relations, Wen said he even plans to join a university team in a game of baseball.

"Both sides, but particularly China, want to put a 'floor"' beneath relations, said David Shambaugh, director of the China Policy Program at George Washington University in Washington, D.C.

Since Abe's visit last autumn, the two sides have tried to set aside rancorous issues dating back to World War II that erupted into sometimes violent anti-Japanese protests in 2005, including a brief siege of the Japanese Consulate in Shanghai by a mob of thousands.

China has long accused Japan of trying to whitewash history, both in comments by politicians and in school history textbooks.

Visits by Abe's predecessor, Junichiro Koizumi, to Tokyo's Yasukuni Shrine that honors dead soldiers -- including executed war criminals -- were the direct cause of the break in contacts, which extended even to one-on-one meetings at multinational forums.

Territorial disputes and conflicting claims to gas deposits in the East China Sea added to the friction, threatening to disrupt thriving economic ties and unnerving neighbors, who urged the two to resolve the impasse.

As Koizumi left office, Beijing and Tokyo moved swiftly to get relations back on track. Abe visited Beijing just two weeks after taking up his post.

"Both sides felt the relationship had hardened too much," said Dali Yang, chair of the political science department at the University of Chicago.

Chinese leaders and the media have toned down their anti-Japanese rhetoric, responding only mildly to Abe's push to reform Japan's pacifist Constitution to give the military a bigger profile. Provocative moves such as Abe's comments downplaying Japan's responsibility for consigning sex slaves to military brothels have drawn an unusually calm response.

Abe, whose popularity at home has slumped, has also stayed away from Yasakuni, although he hasn't said whether he will forgo such visits altogether.

Abe is "trying not to act churlish and looking at the long term," Yang said.

Yet, given the serious and nearly intractable conflicts between Beijing and Tokyo, mere goodwill may have little impact. Wen's mission is more about managing the disagreements than putting them to rest.

Recent efforts by Chinese and Japanese historians to forge a consensus on sensitive wartime events broke down. There is no sign of progress on conflicts over offshore gas drilling, and Japan's bid for a permanent seat on the U.N. Security Council -- a key grievance in 2005 -- remains a nonstarter for China, which holds veto-power as one of five permanent members.

Yet, backsliding into antagonism would suit neither.

"Abe wants to boost domestic support by handling China relations well. China wants stability through improving ties," said Guo Dingping, a Japan scholar at Shanghai's Fudan University.

Wen's visit, which follows a stop in South Korea, will emphasize the positive aspects of relations, including shared interests in trying to resolve tensions over North Korea's nuclear program.

Economic ties will also feature highly: Japan is China's third biggest trading partner and second largest source of foreign investment, with bilateral trade hitting US$207.4 billion (euro155 billion) last year.

Balancing the need for pragmatism while upholding nationalist sentiments will be a key test of Wen's leadership, said Yu Maochun, a history professor at the U.S. Naval Academy in Annapolis, Maryland.

"In all of China's dealings with its neighbors, Japan remains the toughest nut to crack," Yu said.