TOKYO — AN upcoming snap summit between the United States and Japan appears to be the beginning of a new period, in which the two countries downplay trade disputes in order to shore up their security relationship.
The unexpected meeting between President Clinton and Japanese Prime Minister Ryutaro Hashimoto, set for Feb. 23 in Santa Monica, Calif., is ''principally [for the two men] to come to know each other,'' says US Ambassador to Japan Walter Mondale.
But the occasion will not be purely social.
In the background is Mr. Clinton's more elaborate state visit to Japan in mid-April, when the two countries plan to issue a declaration reaffirming their security ties. The two governments are also expected to announce steps to reduce the heavy presence of the US military on the Japanese island of Okinawa, where many residents and legislators have called for an American withdrawal.
Three US servicemen are in the final stages of being tried for the rape of a Japanese girl in Okinawa last September, which raised local tensions, forcing Washington and Tokyo to defend a security pact that has seemed to lose relevance after the cold war.
''Undoubtedly,'' says Mr. Mondale of the Santa Monica summit, ''they will get into how to move ahead on the security declaration and on Okinawa. I think there will be a general discussion on trade, but this will not be a negotiating meeting.''
The days of trade disputes are far from over, but economic issues are on the back burner, say Japanese officials and US observers.
Why US presence in Japan
Analysts here say that at the the Santa Monica summit, Hashimoto may want to consult with his American counterpart over tensions between Taiwan and China, and in doing so suggest to his domestic audience that possible Chinese aggression offers a good reason to keep the Americans around.
One American business executive in Tokyo also suggests that Hashimoto may want to convince Washington that he is a strong supporter of the US-Japan security alliance, since the Japanese leader has gathered a reputation for being tough on Washington.
Under the US-Japan mutual security treaty, signed in 1960, the US protects Japan, and Japan provides the bases and facilities the US requires. Up to 47,000 US troops can be stationed in Japan under current Pentagon guidelines, plus 36,000 in South Korea and 17,000 at sea in East Asia.
A key feature of Western strategy in the cold war, the alliance has lost some of its raison d'etre. The controversy over the Okinawa rape has also highlighted some local dissatisfaction with US presence: crime, noise, and the inconvenience of having a foreign army in the neighborhood.
The US and Japanese governments are struggling to convince their publics and legislatures that the alliance should stay the way it is. The closure of US bases elsewhere in East Asia has made the US military's presence even more important to Washington.
In requesting an informal meeting before the April summit, says Takeshi Sasaki, Tokyo University political scientist, Hashimoto may want to raise concerns about China and Taiwan. ''If such discussions go on in California,'' Professor Sasaki says, ''that can provide our new prime minister ... with a new framework for US-Japan cooperation.''
Neither Japan nor Washington is in a position to define China, whose military has been growing with its economy, as the sort of potential threat that could offer renewed justification for the US-Japan alliance. But Sasaki suggests that Hashimoto may want to hint that way. In drawing attention to a possible political or even military crisis in Taiwan, ''then many Japanese people quite naturally will understand how crucial the US forces in Okinawa could be in the near future.''
Chinese plans to conduct military exercises near Taiwan are reportedly intended to deter voters in a March 23 election from endorsing President Lee Teng-hui's push for a more independent Taiwan. China has threatened to invade Taiwan if it declares independence, though Western analysts say this is unlikely.
Japanese Foreign Ministry officials refuse to say what will be on the agenda in Santa Monica. But Mondale says that Japanese officials raised concerns about Taiwan during recent meetings with visiting US national security adviser Anthony Lake.
Japan's prime minister may also be interested in repairing his image in Washington, says the US executive here, who closely follows bilateral relations.
Hashimoto, particularly in discussions last year over foreign access to Japan's automotive market, has been characterized as a Japanese leader who enjoys saying ''no'' to the Americans.
''Hashimoto wants to enhance his own reputation and credibility as someone who values US-Japan relations, who can solve problems, and who is a leader,'' the executive adds.