

Kasparov had won the first game, lost the second and then drawn the following three. In defeating Kasparov on May 11 1997, Deep Blue made history as the first computer to beat a world champion in a six-game match under standard time controls. The victor was even more unusual: IBM supercomputer, Deep Blue. It’s not uncommon for a defeated player to accuse their opponent of cheating – but in this case the loser was the then world chess champion, Garry Kasparov. The loser reacted with a cry of foul play – one of the most strident accusations of cheating ever made in a tournament, which ignited an international conspiracy theory that is still questioned 20 years later. In just 11 more moves, white had built a position so strong that black had no option but to concede defeat. When black mixed up the moves for the Caro-Kann defence, white took advantage and created a new attack by sacrificing a knight. On the seventh move of the crucial deciding game, black made what some now consider to have been a critical error.
