Researchers Create Computer Program You’ll Never Beat At Poker

David Olson took home $303,909 for winning the 2014 World Series of Poker limit hold’em championship, a feat that simply wouldn’t have happened if a computer program named Cepheus had a say in the matter when it came down to heads-up play.

Researchers from the University of Alberta published a study in Science last Friday claiming to have created a computer program that is essentially unbeatable in heads-up limit hold’em.

Named after the King of Aetheiopia in Greek mythology who left Andromeda chained to a rock to be devoured, Cepheus was trained for 70 days playing matches against itself while considering 6 billion hands per second.

The program started out playing randomly and learned from every loss it suffered, called a “regret value.” The computer would store that regret value for subsequent hands and as matches added up the computer updated its strategy until it approached perfection.

Michael Bowling, the co-author of the study, said, “We’re not quite perfect, but we’re so close that even after a lifetime of playing against it, you wouldn’t know it wasn’t perfect.”

While epic matches in games like checkers and chess have been waged in the past between computers and humans, they differ from poker because it is a game with imperfect information—you only know your own hand and the cards on the table. When IBM’s Deep Blue beat Gary Kasparov in a chess rematch in 1997, the programmers had the advantage of having all of the game’s information displayed on the board.

In the process of programming Cepheus, Bowling and his colleagues were able to confirm some commonly held best practices for heads-up play. For example, the dealer in any given hand has an advantage of .088 big blinds per hand. They also confirmed it’s prudent to raise rather than call in the first move in the vast majority of hands.

Poker geeks can try their hand against Cepheus online. Freelance poker writer Christopher Hall did, and he claims to have come out slightly ahead against the program after 400 hands. While that’s a nice feat for Hall, a creation like Cepheus calls for an epic game against a pro like Phil Hellmuth to show that these researchers have truly solved the game.

(Header image via flickr)