The big challenge for computerised poker players is deception. Poker relies heavily on bluffing, where players pretend to have a good hand when they really have little or nothing.

That might seem like something computers would struggle with, but in fact a program called Sparbot has harnessed game theory well enough to come out ahead of amateur players. And in July 2008, a program called Polaris beat a team of world-class players in a game of Texas hold ’em, the most popular variant of the game.