In May 1997, an IBM supercomputer known as Deep Blue beat then chess world champion Garry Kasparov, who had once bragged he would never lose to a machine.
Kasparov and other chess masters blamed the defeat on a single move made by the IBM machine. Either at the end of the first game or the beginning of the second, depending on who’s telling the story, the computer made a sacrifice that seemed to hint at its long-term strategy.
Kasparov and many others thought the move was too sophisticated for a computer, suggesting there had been some sort of human intervention during the game. “It was an incredibly refined move, of defending while ahead to cut out any hint of countermoves,” grandmaster Yasser Seirawan told Wired in 2001, “and it sent Garry into a tizzy.”
Fifteen years later, one of Big Blue’s designers says the move was the result of a bug in Deep Blue’s software.
The revelation was published in a book by statistician and New York Times journalist Nate Silver titled The Signal and the Noise — and promptly highlighted by Ezra Klein of the Washington Post.
For his book, Silver interviewed Murray Campbell, one of the three IBM computer scientists who designed Deep Blue, and Murray told him that the machine was unable to select a move and simply picked one at random.