American, British and Australian rock musicians like to work Japan - not only because they are paid in yen, a currency worth more than their own, but also because Japan has spawned tribes of groupies who dispense their sex freebies at the crook of an index finger.

The Japanese groupies have become so notorious in rock circles that the wives of foreign musicans performing in Tokyo, Osaka and other cities insist upon accompanying their husbands.

The situation has created difficulties for the Japanese talent agents who book the rock tours. But the bookers are resourceful. They have hired so-called "guides" whose main function is to take the wives on shopping tours while their husbands make out with the groupies.

In a recent in-depth study of the groupie phenomenon, Shukan Asahi, a Japanese publication, revealed that the groupies consist of virgins, sexually liberated non-virgins, and in some cases homosexual boys - most 12 to 23 and obsessed with the rock culture.

For the most part, these groupies come from middle- or upper-class families. Their fathers are usually corporation executives or successful merchants. Some are college girls who take time out from their studies to follow their favorite rock bands from city to city for a week or 10 days. One such traveling groupie described herself as "a wife for a night who could speak no English but learned very quickly to speak the universal language of love."