Young Chess Masters on the March. WORLD-CLASS WINNERS

THE sight of a precocious 9- or 10-year-old knocking off a relatively strong adult chess player used to be rare enough to cause a sensation. Even Bobby Fischer didn't start doing such things until he was 12 or so. But so many little prodigies are coming along at younger and younger ages that scenes like this have become commonplace. Most big tournaments have a number of youngsters running around - many of them far more skilled than the average adult. A typical example was the 1989 United States Amateur Team Championship-East here, a popular event that annually attracts close to 1,000 players of all ages and levels of ability to this central New Jersey site.

Because of its team format, its more relaxed atmosphere, and its setting in a hotel with swimming pool, exercise rooms, and video games, this particular tournament appeals to the younger set even more than do regular individual events. The kid-beats-adult scenario is thus magnified.

A case in point was 10-year-old John Viloria of Yonkers, N.Y., who already is rated one step below master, making him one of the strongest players his age that the US has produced. Playing for one of several all-scholastic teams fielded by the veteran New York master and teacher Jack Collins, he compiled a 5-1 individual result, losing only to the strong adult master Mark Ginsburg.

Viloria is only one of an impressive group of young players who have begun to boost the prestige of US chess worldwide.

He won the world under-10 championship in Puerto Rico two years ago and again in Romania last year. Another world age-group champion is Ilya Gurevich, 17, of Worcester, Mass., who won the under-14 title a few years ago and has twice finished second in the under-16 competition.

Americans have also done well in the girls' divisions of these competitions. Susan Urminska of Kapaa, Hawaii, won the world under-10 title two years ago, Yvonne Krawiec of Hacienda Heights Calif., won the under-12 championship, and Jessica Ambats of New York City just missed under-14 honors on tiebreaks. That's just the iceberg tip.

``We have more and more kids who are stronger and stronger all the time,'' says Allen Kaufman, executive director of the American Chess Foundation, which helps support youth chess. There are more masters under age 21 than ever, he adds.

What draws a particular child to the game, and how does great potential first show itself?

The answers can be as varied as the individuals involved, but in a surprising number of cases it seems to have been a fluke that lit the initial spark.

Take K.K. Karanja, ex-national primary and elementary champion and now the highest-ranked 15-year-old in the US.

IN 1980, K.K.'s parents were planning a trip to their native Kenya, so they took the 6-year-old to buy some things to play with while they were away. To their amazement, since neither parent knew anything about the game, he picked a chess set.

``The rules were on the box, and while we were gone he taught himself to play,'' recalls K.K.'s father, Edward, a philosophy professor at Brooklyn College.

Viloria grew up in a non-chess family too, but there was method to the way he got into the game.

``When he was 2 he was adding two digits at the snap of a finger,'' recalls his father, Oscar. ``At 4 he could do square roots. .. I knew chess was a good game for the mind, so I got books from the library. Pretty soon he was beating me.''

John soon zoomed to the top of his age group, winning many national honors and then capturing those two world titles.

Living in or near a major chess center is not a prerequisite: Alex Chang of Richwood, West Va., got excited about the game at age 5 when he saw some older children with a trophy. His non-playing parents took him to a school club, and pretty soon he was beating many older players.

Geography was against him, but his parents arranged lessons with a master from the nearest big city and bought a computer for him to play against.

That was enough for Alex. He burst into prominence in 1983 as a tiny first-grader, contending for national elementary honors (6th grade and under), and sharing the primary title, which goes up to 3rd grade. By the time he was in 4th grade he was elementary champion.

Susan and Natalie Urminska live in the even more remote community of Kapaa on the Hawaiian island of Kauai - but that hasn't stopped these twin sisters from achieving high national rankings, with Susan also capturing the world title for girls under 10 two years ago. And once again, it all started with a chance occurrence.

Their parents emigrated from Czechoslovakia in 1969 and eventually settled in Hawaii, where the girls were born. An older brother learned the game and was playing with a friend while babysitting for his sisters. The girls, then 3, became intrigued by the pieces. The rest, as they say, is history.

The proliferation of young talent stems from many factors, including more organized instruction and more opportunities for tournament play.

The dedication required can't help but involve some sacrifices - socially, academically, athletically. And one result is a certain amount of ``burnout,'' just as exists in gymnastics, figure skating, ballet, and other high-intensity, time-consuming activities.

All the lessons, travel, lodging, fees, etc., can be expensive for parents, too - sometimes running into thousands of dollars if a child is good enough to qualify for international tournaments.

Where will it all lead? Probably not, in most cases, to a chess career. Despite improvements, earning a living from the game is still a chancy undertaking in the US. So while some may take a shot in that direction, most will probably opt for more conventional jobs.

They'll have moments of glory to look back on, though. And according to Edward Karanja, they will have something more.

``Chess involves discipline and mental stimulation,'' he says, ``It also teaches you about winning and losing - and how losing can be good sometimes. That's a hard concept, and a good one to learn.

``This is not only a game or an mental exercise - it's a great teacher of the lessons of life.''