What sort of person is Yasser Seirawan, the United States chess champion? The constant flow of chess news, national and international, has pre-empted a profile that appeared recently written by Dick Rorabeck of the Los Angeles Times.

"He is hale, hip and handsome. He swims, skis, surfs, is as devastating in karate as he is in tennis. He is a hustler and a notorious ladies' man and surfaced a few years ago as Cosmo's `Bachelor of the Month.' He even reads voraciously. And on the side, Yasser plays a little chess." So says Rorabeck.Seirawan was born in Syria, but he is quintessentially a Yank.

When asked if he thinks he can beat Kasaprov and/or Karpov, if he ever has the opportunity to play them, he answers, "I already have."

Seirawan, at 28, is gregarious, witty, affable and outrageous enough to justify his self-characterization as "the John McEnroe of chess." He is opinionated as well, competition chess is no matter for the mugwump - he is more than willing to defend his position:

- In spite of its elitist, vaguely wimpy image, chess is a sport, demanding, draining, hairy-chested.

- The Soviets, pre-eminent in chess, got where they are by cheating.

- Women, not to put too fine a point on it, are marvelous companions but terrible chess players, always will be.

Seirawan tells of a recent plane trip enroute to a tournament:

"My seatmate, a lady, asked where I was going?"

"Madrid."

"Business or pleasure," she asked.

"Business."

"What's your business?"

"Chess. I am an international grandmaster."

"She looked me up and down, finally she says, `Oh, no you're not.' "

"I'm young, articulate, well-traveled, well-read. I obviously didn't fit her conception of a chess player - either a prodigy in bottle-bottomed glasses or a bearded old egghead.

"The image of the reclusive introvert may have derived from Bobby Fischer's heyday, but most professional chess players are like me, young and vital.

"A 45-year-old is at a disadvantage because chess is a sport. This is not a dry, scientific search for truth - although it's that too. It's a fight between two individuals, a battle of wills, with an unbelievable expenditure of energy. During an extended match, a player can - does - lose 25 to 30 pounds.

"When I play a single game of tournament chess that lasts four to five hours, I am mentally and physically out. I hit the hotel room and collapse, just hoping I have enough energy for the next day.

"The nervous tension! It can kill you! A fumbled pass, a missed free throw, a netted tennis shot can't begin to compare to a bad chess move."

By his own exuberant admission, Seirawan loves life, lives it to the hilt. He has done so, in fact, since his family fled Syria when Yaz was two. The Seirawans (English mother, Syrian father - "a computer genius," says Yasser) settled in England then moved to Seattle.

The clan (including a brother and sister) roamed America and Mexico in a station wagon, during which young Yasser became an accomplished "pinball hustler, pool hustler, 4.0 student - a tremendous life."

"Do I have a killer instinct? Yes. Absolutely yes. It's possible that my persona masks it. Everybody tends to think of me as a nice guy.

"I want to win. And I'll kill if I have to, metaphorically speaking, of course!'

And, finally, inevitably, on beating the Soviets?

"The world title would be worth millions of dollars. Millions. But - and I know it sounds like a cliche - the money pales. The sheer beauty is the thought that you've beaten the Soviets at their own game, their national sport. Man! Never mind the money. Never mind the bread and never mind the water. You could live on that thought forever!"