CHESS CHAMP FACES DEEP BLUE\Kasparov to play 6-game regulation match against computer.

Byline: Bruce Weber The New York Times

In the rarest of occurrences in the chaotic chess world, Garry Kasparov, the reigning world champion, is to take the stage at the Philadelphia Convention Center to begin a match Saturday afternoon against an opponent who has no complaints about him.

The administrative turmoil, petty jealousies and personal grievances that are the constant undercurrent of top-flight chess will be set aside. Absent, too, will be the brute psychology that is a pivotal aspect of chess, both away from the board and over it.

When Kasparov sits across a chessboard from an IBM technician, taking instructions from a computer in Yorktown Heights, N.Y., the question will be simple: Can the world's strongest chess player hold off the world's strongest chess machine in what will be history's first multigame regulation match between a world champion and a computer?

The prevailing opinion among chess experts is yes. Still, there is considerable interest in how far computer chess has progressed in its inexorable march to superiority.

"It's a legitimate match," said Yasser Seirawan, a grandmaster who publishes Inside Chess, a magazine for competitive players. "Garry will win, say 4-2, but I think 4-2 is not too shabby. But whether a machine beats Kasparov today or in 10 years, it's inevitable."

Over the last two decades, computers have had growing success against chess grandmasters, particularly in speed competitions, where decision-making time is severely limited and the computer's advantage in rapid calculation is maximized. Indeed, the new computer, known as Deep Blue and developed over the last six years by five scientists at the International Business Machines Corp., is the fastest ever, capable of searching up to 50 billion chess positions in three minutes.

But this match, six games in eight days, is the first of its kind, pitting a machine against the world champion under standard match conditions - that is, a series of games in which each player has two hours to make his or its first 40 moves.

The added time, which the computer can use for deeper calculation and analysis, allows a human player to probe his imagination and creativity, qualities that Kasparov, who has been world champion since 1985, has proved to possess in abundance. Although he has lost the occasional speed game to a computer, he has never been beaten by one in a single regulation game. In 1989, he trounced the predecessor of Deep Blue, known as Deep Thought, in consecutive exhibitions.

Deep Blue combines parallel processing technology with advances in chess-specific processor chips and updated software, including new chess evaluation programs and extensive databases, and is an improvement on previous chess computers in several ways, its designers say. For one thing, it can calculate farther out along the "trees" of possibility created by any given chess move. For another, its evaluative strength has been augmented through experiments in programming.

The computer works by analyzing all possible moves and assigning to them numerical values based on chessboard features it recognizes. There are thousands of these features, like pawn strength, control of given squares and threats to the opposing king. The programmer's task is to assign weights to them, so that the computer can assess a position numerically. Such assessment, of course, is what a human player does by using intuition, experience and ingenuity.

"You don't have to be that strong a player to program a computer to play much better than yourself," said Murray Campbell, one of the IBM research scientists, whose rating of 2,100 classifies him as an expert chess player.

Ratings, determined by the International Chess Federation, measure the relative success of players in recent federation tournaments.