Tokyo and Beijing first agreed to reciprocal warship visits seven years ago, but China canceled a planned port call in 2002 after then-Prime Minister Junichiro Koizumi visited Yasukuni Shrine, seen in China as a symbol of Japan's past militarism.

Bilateral ties, long plagued by bitter Chinese memories of Japan's wartime invasion and partial occupation, grew frigid during Koizumi's five- year term but began to thaw after his successor Shinzo Abe's ice-breaking visit to Beijing last year.

"After the relationship became so poor under Koizumi, it's very important to show that we now have a rational relationship. It's an important public gesture," said Phil Deans, a professor at Temple University in Tokyo, referring to the warship's visit. "It shows they are talking to each other in a grown-up way again after many years of shouting at each other over the wall."

Japanese Defense Minister Shigeru Ishiba yesterday lauded the coming port call by Chinese missile destroyer Shenzhen.

But in a sign of simmering concerns about China's drive to modernize its military, Ishiba told a news conference: "We should always watch closely how it functions in China's vast territory, which shares borders with 14 countries," Kyodo news agency said.

Japan is anxious over China's military buildup despite Beijing's assurances its armed forces are only for self-defense.

China said in March it would boost defense spending by 17.8 percent to about HK$45 billion (HK$350 billion) this year, but a Pentagon report warned that Beijing's total military-related spending could be more than double that.

China's navy is rapidly modernizing and transforming from a coastal force into a blue-water naval power with more than 20 new amphibious assault ships and nuclear-powered attack submarines.

China is equally wary of Tokyo's intentions as Japan pushes the limits of its post-World War II pacifist constitution in search of a bolder global and regional security role.

"Since the end of the Cold War, and especially in recent years, Japan, hungry for international recognition and matching status, has been chasing after the goal of becoming a political and military major power in the name of being a `normal nation' again," wrote Rear Admiral Yang Yi, an expert with China's University of National Defense, in the China Daily yesterday.

"Right now, China and Japan are looking at a critical window of opportunity for developing their bilateral ties," Yang said, adding the two countries should spare no effort to bolster cooperation in maritime security and reduce mutual suspicion.

Incumbent Japanese Prime Minister Yasuo Fukuda, who took over in September after Abe abruptly resigned and who stresses the need for closer ties with Japan's Asian neighbors while keeping Tokyo's security alliance with Washington tight, will likely seek to maintain the momentum in improving ties.

That means that conservative anti-Chinese ruling politicians more inclined toward containing than engaging Beijing may for now be less influential, analysts said.

"I don't think it [containment] will disappear but it will get less emphasis," Deans said. "They will keep it in the drawer and recycle it in future." Fukuda, who held his first summit with Premier Wen Jiabao this month at an Asian leaders' gathering in Singapore, has promised to visit Beijing as soon as possible. President Hu Jintao plans a state visit to Japan next year.

Still, mistrust runs deep on both sides and feuds over territory and resources in the East China Sea remain unresolved.

"They have not restored a relationship of trust. To achieve that, they need confidence-building measures," said Tomoyuki Kojima, a China expert at Keio University in Tokyo. "They are finally at the starting line."

REUTERS