Chinese Premier Wen Jiabao goes to Japan on Wednesday promising a strategic pact, energy cooperation and maybe a crowd-pleasing baseball cameo as the two nations seek to narrow rifts over history and regional ambitions.

Beijing has cast Wen's three-day visit as an "ice-thawing" trip to ease bitterness left by then-Japanese prime minister Junichiro Koizumi's visits to the Yasukuni war shrine, seen by many in Asia as a symbol of Tokyo's past militarism.

Incumbent Prime Minister Shinzo Abe made an "ice-breaking" visit to China after taking office last September. He and Wen are set to announce a broad pact intended to tame volatile friction.

"The history dispute is really part of a wider pattern of strategic distrust and discord," said Zhu Feng, an international security expert at Peking University.

"Both countries know that as they rise, they need to contain friction and avoid letting conflicts expand. Wen's visit is just an initial step in that direction."

Wen, on the first visit to Japan by a Chinese premier since 2000, will court a public grown wary of Beijing's growing economic and diplomatic shadow.

As well as addressing Japan's parliament, he wants to play baseball with university students in Kyoto, he told Japanese reporters last week.

Before Japan, Wen visits South Korea from Tuesday to discuss a possible free trade agreement. The summits in Seoul and Tokyo will also cover North Korea, scheduled to shut a nuclear reactor by mid-April in a nascent disarmament plan brokered by Beijing.

NOT SMOOTH SAILING

Not even Beijing's state-run media, which have recently lauded better ties with Tokyo, pretend the road ahead will be easy. Past efforts to ease tensions have foundered amid feuding over history.

On Sunday, a newspaper issued by the Party's elite Central Party School accused Abe of muddying hopes through recent comments doubting that "comfort women" were forced into sexual slavery for Japan's invading armies.

"Just as the theme of strategic mutually beneficial relations has injected fresh vitality into Sino-Japanese relations, Japan has been constantly making discordant noises," commented the Study Times.

Ties between the two neighbours "can't possibly always be smooth sailing", the paper said.

Last week Wen urged Abe to avoid the Yasukuni Shrine, which honours 14 leaders convicted by an Allied tribunal as Class A war criminals along with some 2.5 million war dead.

Abe has paid his respects there in the past, and has refused to say whether he will visit the shrine while in office.

The Chinese premier, 64, was born in the northern Chinese port city of Tianjin under Japanese occupation.

Abe, 52, Japan's first prime minister born after World War Two and grandson of a wartime cabinet minister, has remained ambiguous in interviews with Chinese media ahead of Wen's visit.

"I want to maintain the feeling of mourning those who gave their lives for their country, but since this has become a diplomatic problem, I do not intend to say whether I will go or not," he told Hong Kong-based Phoenix satellite television, according to a Japanese official.

ENERGY CONTENTION

As well as contentious wartime memories, Wen and Abe will have to grapple with volatile present-day disputes that reflect the two nations' contending regional ambitions.

Japan remains the economic titan of Asia, with a $4.5 trillion economy, about double the size of China's, according to World Bank numbers from 2005. Tokyo wants to translate its economic might into diplomatic clout.

But China's economy is set to speed past Japan's in coming decades, and it is wary of Abe's plans to rewrite his country's constitution to allow more military action.

For its part, Japan is worried about China's military build-up and Abe has urged China to be more transparent about its rising defence spending.

The two leaders are also due to talk about energy cooperation, especially transferring Japanese waste-cutting technology. But they remain far apart in a maritime territorial dispute focused on energy needs.

Officials from the two nations -- the world's second and third largest consumers of oil -- met in Beijing on Friday for more talks over disputed parts of the East China Sea, which holds oil and gas coveted by both countries.

The discussions ended without Beijing offering any new data or information requested by Japan, Kyodo news agency reported.

Beijing and Tokyo disagree over the boundary between their exclusive marine economic zones, and Japan objects to Chinese development of gas fields near the sea boundary. It fears drilling there could drain gas from the side claimed by Tokyo.