When world chess champion Garry Kasparov abruptly resigned the sixth and final game of his match in May against Deep Blue-a.k.a. the IBM RS/6000 SP supercomputer-a machine finally fulfilled one of the oldest challenges in artificial intelligence. Chess has tantalized computer researchers since the 1830s, when the eccentric English inventor Charles Babbage thought of luring investors to his idea of a programmable “analytical engine” by holding out the possibility of a chess-playing machine. After all, the rules of chess are precisely defined and easy to program, yet they give rise to strategic complexities that challenge the finest human minds. But despite researchers’ best efforts, no machine proved able to beat the finest human players. Until Deep Blue.

Ironically, the victory comes when the computer-chess community has long abandoned any pretense of mimicking human thought. Chess masters, like the rest of us, are now known to reason by recognizing patterns, forming concepts, and creating plans-processes that computers do poorly, if at all. Deep Blue, like all the top chess-playing machines since the 1960s, relies instead on brute force-it looks as far ahead as it can at all possible moves and evaluates the strength of each position according to preprogrammed rules. Because of the rule that the faster the computer, the more positions it can search and the better it can play, Deep Blue relies on 32 high-speed processors operating simultaneously, each coordinating the work of 16 special-purpose “chess chips” that run in parallel. This computing firepower enables Deep Blue to evaluate a total of 200 million positions each second.

M. Mitchell Waldrop, author of the bestseller Complexity and of a forthcoming book on the history of computing, recently spoke with Deep Blue’s principal designer at IBM, Feng-Hsiung Hsu, about the implications of the machine’s victory and its value for other uses.

TR: In February 1996, when Deep Blue was brand new, it went up against Garry Kasparov and lost. Many people felt vindicated-as if that proved the human mind’s innate superiority over a mere machine. But now that Deep Blue has won, many feel as if the computer has humbled humanity. Should they feel threatened?

HSU: No. Remember, Deep Blue didn’t play chess by itself. Before the match even started, humans programmed the machine to rise to Garry’s level. And then during the match we actually went in between games, looked at Deep Blue’s mistakes, and adjusted its criteria for evaluating the situation accordingly, so it wouldn’t make the same mistake twice. Without that, Deep Blue could not have competed with Garry. So you could say that last year, Garry won one for humanity’s past. This year, Deep Blue won one for humanity’s future.

TR: How so?

HSU: When Garry plays chess, he is relying on the intellect he is born with, his knowledge of the game, and the experience he has gained from playing both people and computers. This is the old-fashioned way of playing chess; Garry, despite his brilliance, is limited by what is biologically possible. Deep Blue represents any technology that allows us to exceed the limits nature normally imposes on us. Right now we’re talking over the telephone: just by shouting I cannot reach you. The principle is the same with chess. Garry may be the top player ever in chess, but while the chess players on Deep Blue’s team can’t claim to reach anywhere near Garry’s ability, with Deep Blue we exceeded our limits and won.

TR: When you put it that way, the match sounds a little unfair. Garry wasn’t playing against one machine or even one person but a whole team.

HSU: But Garry was also part of a team. Between games he would consult with his coach, and even his own chess computer, to find out more about what Deep Blue would do. That is actually a normal part of any master’s-level chess match. So you could say that Garry was playing against a computer relying on human power-but Deep Blue was playing against a human relying partly on computer power.