On one side of the board, 1.5 kilograms of gray matter. On the other side, 480 chess chips. Humans finally fell to computers in 1997, when IBM’s chess-playing computer, Deep Blue, beat the reigning world champion, Garry Kasparov. Each of Deep Blue’s chips consisted of 1.5 million transistors arranged into specialized blocks—such as a move-generator logic array—as well as some RAM and ROM. Together, the chips could churn through 200 million chess positions per second. That brute-force power, combined with clever game-evaluation functions, gave Deep Blue decisive moves that Kasparov called “uncomputerlike.” These moves “exerted great psychological pressures,” recalls Deep Blue’s mastermind, Feng-hsiung Hsu, now at Microsoft.
Since Deep Blue’s victory, more and more games in which human intelligence seemed to have the upper hand have fallen to the machines: in 2016, Google’s AlphaGo beat the world’s best Go player, Lee Sedol.