In the wondrous world of diplomacy, there are formal negotiations, official communiques, state visits, direct contacts between statesmen of their envoys -- and also sounds, like high-pitched dog whistles, that only diplomats can hear.

Consider, by way of illustration of that last category, the extremely tentative, seemingly trifling concessions dangled the other day before Rep. Stephen Solarz (D-N.Y.) by North Korea's rough, tough President Kim Il Sung. Solarz had no standing as a representative of the U.S. government, but he was the first American official to talk to a North Korean official in Pyongyang since the Korean War.

And Kim didn't offer all that much, when you consider the incendiary state of hostility between the two Koreas and between North Korea and the United States. Peace talks have gotten nowhere, over almost 30 years. Large armies face each other across the truce line. Kim had nothing much to say directly about all that.

What he did, however, was to break a small patch of new ground. He offered scholarly and cultural exchanges with the United States. Perhaps more important, he pointedly droped a pre-condition to the reunion of families and the resumption of mail deliveries between the two Koreas. It would have required that South Korea first repeal a law that makes it a crime to be a communist.

He spoke also of opening trade relations with the South. But he held fast to his well-established refusal to allow South Korea to sit in as a full partner on the endlessly fruitless peace talks.

No big change of heart in all of that. But then, the State Department's Korean experts are quick to point out, the journey to "normalization" of relations between the United States and mainland China began with Ping-pong.

What they mean is that in the resolution of an international conflict that has, if anything, been hardening for three decades, it is the direction of movement, much more than the pace, that counts.This is all the more so when you consider what's at stake for the United States. Other than Berlin, where the danger of an outbreak of fighting has eased considerably over the years, the Korean cease-fire line is the only place in the world where American armed forces are squarely confronting those of a well-armed adversary with which there still exists, in a technical sense, a state of war.

So there is no way the United States could not be involved in any serious outbreak of Korean hostilities.

Short of that, the interest in easing tensions is all the greater at a time when American committment to the South Korean government is increasingly a source of embarrassment -- or worse. The first signs of weakening support for the brutally repressive military regime now tightening its authoritarian hold is taken as betrayal, in Seoul and among South Korea's loud champions in this country.

Yet unquestioning reinforcement of the military government, with economic as well as military help, calls into question the U.S. commitment to "democracy" and "human rights." The result is a tangle-footed sort of two-step approach: one step backward to show, symbolically, our disapproval, by briefly holding up an Asian Development Bank loan, for example, and one step forward in letting an Export-Import Bank loan go through for fear of actually damaging the South Korean economy or demoralizing the government.

To give you an idea of the fineness of the fine-tuning involved, the State Department recently gave clearance for the American Army chief of staff to visit South Korea. But it politely "suggested" that a visit by the secretary of the Air Force be canceled. The former, it was said, had a clear "chain of command" interest in inspecting his forces on the scene; the latter's trip, it was explained, "would not support any essential security function."

In the case of Solarz (a tireless overseas traveler but also well regarded at State as a responsible and competent unofficial intermediary), the department publicly "neither encouraged nor discouraged" his visit (more sounds that only diplomats can hear). But privately there was enthusiasm. And Assistant Secretary of State Richard Holbrooke is now prepared to welcome it as a "positive event that didn't weaken South Korea's stability, and might ease tensions."

The question, of course, is how positive it will turn out to be -- how much Kim really wants to ease tensions and whether he is prepared to confirm what he said to Solarz through more conventional channels. Discreet follow-ups are under way. Even the South Koreans expressed guarded interest in testing Kim's intentions.