in the popular recounting of Kasparov’s match against Deep Blue, it was the second game in which his problems originated—when he had made the almost unprecedented error of forfeiting a position that he could probably have drawn.

but what had inspired Kasparov to commit this mistake? his anxiety over Deep Blue’s forty-fourth move in the first game—the move in which the computer had moved its rook for no apparent purpose. Kasparov had concluded that the counter-intuitive play must be a sign of superior intelligence. he had never considered that it was simply a bug.