Tokyo — Washington and Peking appear to have decided mutually that their global strategic interests outweigh their disagreement over Taiwan.
And Tokyo, the party in between, has greeted the compromise over arms sales to Taiwan announced Aug. 17 with an almost audible sigh of relief.
Diplomatic observers here and in Peking point out that the strategic imperatives that brought President Nixon to Peking 10 years ago and that induced former President Carter to open an embassy in Peking at the cost of severing treaty ties with Taiwan seem in the end to have prevailed. The strategic viewpoint shared by Washington and Peking is that Soviet expansionism and ''hegemonism'' are the main threats to world peace.
The compromise over the Taiwan issue - which Peking warns is not a final solution, only a ''beginning step'' - opens the way to a military relationship between Peking and Washington.
Such a relationship, which remains one of the fascinating imponderables of the Sino-Soviet-American triangle, seemed to be budding during the Carter administration's days. But it wilted when President Reagan came to office and pledged to improve American official ties with Taiwan. Mr. Reagan has now in effect abandoned this campaign pledge.
Peking insists that although it is far behind the Soviet Union in terms of sophisticated modern arms, it is not intimidated since its strength lies in defense in depth, not primarily in a threat to strike at the Soviet Union.
There is also a question whether Peking could pay for meaningful imports even of so-called dual-use American technology - technology useful in peace and in war.
But the Taiwan arms sales compromise does once again make a military relationship between Peking and Washington an actively explorable subject.
At the same time, Taiwan need not necessarily be the loser, Western analysts say, if the unspoken assumptions on which Washington and Peking based their compromise are carried through to their logical conclusions.
Washington assumes that Peking will not try to ''liberate'' Taiwan except by peaceful means. Peking assumes that the US will truly diminish its arms sales to Taiwan and that eventually these sales will cease altogether.
Peking insists that how it chooses to reunify Taiwan is its own internal affair, which brooks no interference by outsiders. But if it shows in deeds that its real intentions toward Taiwan are peaceful, there is no need for large American arms sales to that island.
What the joint communique announced by the two governments says in effect is that Washington trusts Peking's intentions while Peking also expects an actual diminution of Washingtons arms sales to Taiwan.
On both sides, a margin of distrust remains. Peking refuses to commit itself explicitly to the peaceful reunification of Taiwan, while Washington specifies neither a time limit nor a meaningful reduction in arms sales to Taiwan.
Technically, it could supply up to $830 million a year, the amount former President Carter sold to Taiwan in 1979. If sales continued at anywhere close to this figure, or even half this figure, Washington's declaration of intent ''gradually to reduce its sale of arms to Taiwan'' will sound hollow indeed.
Peking is engaged in an attempt to persuade Taiwan at least to talk about reunification, and if not to talk, as a minimum to permit trade, communications with the mainland. So far Taiwan has rebuffed every attempt.
Any American commitment to reduce arms sales to Taiwan, even without a promise to cut them off altogether, helps Peking bring pressure to bear on Taiwan.
But Taiwan, important as it is both to Peking and to the United States, is, as the joint communique points out, an issue ''rooted in history.'' What matters more to both today is the threat of Soviet expansionism on a global scale.