The grapevine bills it as the only bar for homosexuals in the Soviet capital.

It sits inconspicuously on a side street near the Kremlin, and compared to other Moscow night spots where long lines gather at the front door, access is easy.

Inside, simple Russian food, wine and conversation flow freely until the late night hours and slowly give way to cognac and raucous laughter, according to regular patrons.

The place, one waitress said, is always full. The clientele seems to be a tight-knit circle of men, ranging from late teens to early 50s. Altogether, some 60 to 70 men -- and a few women -- sit engaged in conversation in twos or fours at simple tables in four public rooms lit by large wrought-iron lamps.

They don't often use the slang word, "gay." Other Soviets refer to homosexuals as goluboi -- the Russian word for "light blue."

In the Soviet Union, "persons inclined to sexual perversions" -- homosexuals -- are subject to imprisonment for several years. But that does not appear to inhibit a light atmosphere or occasional petting between customers, even after a uniformed policeman stations himself inside the front door and begins chatting with customers.

A clubhouse atmosphere prevails, with patrons hopping from one table to the next, chatting freely with the staff members, all women.

In a small room, behind a closed door, men and women dance vigorously to loud Russian music.

An American guest, a stranger to the environment, feels quickly out of place. The regulars are slow in warming up to him.

After a while several do exchange small talk, and eventually talk in cryptic terms about their "free life," and regular meetings in the bar, which they say has been running for several years.

In reponse to questions about AIDS -- the disease plaguing homosexuals and others in several western countries -- everyone asked says he has heard of it, and three men in their mid-40s say they also know of cases in the Soviet capital.

Here, AIDS is known as SPID, (pronounced "speed") for its Russian acronym. Yes, they say, they know about it. They have read in Soviet newspapers that it is a major epidemic in the West.

"Afraid of it?" one responds to a question. "Not really -- well maybe. I don't know that much about it."

The questions from a stranger about AIDS seem to make them uneasy. They slip back into small talk, joking about each other, occasionally talking about films or plays.

The clientele does not seem to be marked by the fashions sometimes worn by western counterparts, such as leather clothes or short hair. Most are dressed in sweaters and jeans or corduroys, some in suits.

As the night wears on the conversation rises, and then falls, as in most any bar until slowly, two by two, the customers leave.