IN Moscow this week, two Soviet citizens - Anatoly Karpov and Gary Kasparov - have launched what could be a months-long battle for the world chess championship.
In America, however, any mention of the royal game still elicits the same question it has since 1972: What ever happened to Bobby Fischer?
Fischer's defeat of his Soviet rival, Boris Spassky, that year was about the only time chess captured the imagination of the man on the street in this country. Even those who assumed the Sicilian Defense was something out of ''The Godfather'' were caught up in the excitement during the two months it took the whiz kid from Brooklyn to wrest the title from the Russian.
In that match, of course, there were the cold-war overtones of an American challenging the decades-long Soviet domination of the game. And there was Fischer himself - a player whose brilliant accomplishments at the board and bizarre behavior away from it intrigued and fascinated the public.
But Fischer, who went into hibernation after that victory and forfeited his championship, now lives as a recluse in California. Subsequent title matches - even with the built-in drama of a Soviet defector, Viktor Korchnoi, cast in the challenger's role in 1978 and '81 - just didn't arouse the same excitement.
On the surface, then, the current struggle between two Soviets appears less dramatic in human and international terms than Karpov's successful defenses against Korchnoi. But the quality of the chess is expected to be much higher in this match. And the interest in the United States, even among laymen, has reached a surprisingly high pitch - as evidenced by the extensive television coverage. A network of 118 Public Broadcasting System affiliates plans to carry a weekly two-hour program on the play, hosted by New York master Shelby Lyman. Mr. Lyman served as host for the broad coverage given to the Fischer-Spassky match from Reykjavik, Iceland, 12 years ago, as well as the more modest coverage of the two Karpov-Korchnoi encounters.
Why such interest? For one thing, this year's match brings together two rivals generally acknowledged to be the very best in the world - something that doesn't always happen in any sort of competition, because of upsets along the long and circuitous routes to the finals.
Karpov, who won the title by default when Fischer declined to defend in 1975, is an outstanding champion. He held onto his title firmly in the two matches with Korchnoi. And he has shown his overall superiority year in and year out in the world's major tournaments. At 33, he is presumably at the very peak of his game.
Kasparov, however, is just 21 - the youngest challenger in history. But Kasparov's spectacular play in tournaments over the past three years, climaxed by a succession of impressive victories in the Candidates' Matches leading up to this showdown, make him the only logical challenger.
Indeed, Kasparov's game has been so strong that he recently surpassed Karpov to assume the No. 1 position in the International Chess Federation's computerized ratings. Despite his youth, many experts see him as the more formidable player - and look for him to win.
Despite its appearances as an all-Soviet show, this year's match has its own version of the East-West conflict inherent in the Fischer-Spassky duel. This time it comes in the form of a battle between a Kremlin protege and an outsider. Karpov is the darling of Soviet officialdom - the party-line Muscovite who seldom strays from the straight and narrow in word or deed. Kasparov, on the other hand, is from Baku in the remote republic of Azerbaijan, and is half-Jewish - not exactly the type the Kremlin would like to see take the title, one presumes.
To be sure, this sort of situation existed to an even greater degree during Karpov's 1978 and '81 defenses against Korchnoi, a ''nonperson'' in the USSR because of his defection. But in both those matches the champion was a heavy favorite, while this year's outcome is considered a virtual tossup. (The match began with a draw on Monday.)
Furthermore, the Moscow site is more in the mainstream than those of the two Karpov-Korchnoi confrontations, which were held in the remote city of Baguio in the Philippines and in the Italian mountain town of Merano - although the Kremlin has negated this advantage so far by its unwilingness to issue visas to journalists attempting to cover the match.
Helping to analyze Karpov's and Kasparov's moves on American television will be a succession of US and foreign chess personalities - including Spassky, who moved to Paris with his French-born wife in 1976. Spassky announced this summer that he would no longer compete under the Soviet flag but would represent France in international events.
How long will the competition last? No one is sure. The conditions of the Karpov-Kasparov match are that the first player to win six games is the victor, with draws not counting. This ''open ended'' setup, which was also in force in 1978 and '81, is a departure from the old 24-game matches played in the previous era up to and including the Fischer-Spassky encounter.
The major advantage of the current system is that a player who gets ahead no longer has any incentive to turn cautious and try to keep getting draws until the required number of games has passed. The disadvantage, however, is that it is difficult for all involved - including those putting up money and organizing the event - to plan for a contest of such indeterminate length.
The schedule calls for three games a week - on Monday, Wednesday, and Friday, with adjourned games completed the following day. If past performances are an indication, it will take at least two to three months before either player achieves the necessary six victories.
If Karpov retains the title, his next defense (under rules put into effect last year) will be in 1986 - after two years, instead of the former three. But under another recently restored provision, the champion has the right to a rematch within six months if the challenger wins.
Which just could make this one of the longest chess seasons in recent memory.