Chinook is a computer program that plays English draughts (also known as checkers), developed around 1989 at the University of Alberta, led by Jonathan Schaeffer. Other developers are Rob Lake, Paul Lu, Martin Bryant, and Norman Treloar. In July 2007, Chinook's developers announced that the program has been improved to the point where it cannot lose a game.
Man vs. Machine World ChampionEdit
Chinook is the first computer program to win the world champion title in a competition against humans. In 1990 it won the right to play in the human World Championship by being second to Marion Tinsley in the US Nationals. At first the American Checkers Federation and English Draughts Association were against the participation of a computer in a human championship. When Tinsley resigned his title in protest, the ACF and EDA created the new title Man vs. Machine World Championship, and competition proceeded. Tinsley won with four wins to Chinook's two, with 33 draws.
In a rematch, Chinook was declared the Man-Machine World Champion in checkers in 1994 in a match against Marion Tinsley after six drawn games, and Tinsley's withdrawal due to pancreatic cancer. While Chinook became the world champion, it had never defeated the best checkers player of all time, Tinsley, who was significantly superior to even his closest peer.
In 1995, Chinook defended its man-machine title against Don Lafferty in a 32 game match. The final score was 1-0 with 31 draws for Chinook over Lafferty. After the match, Jonathan Schaeffer decided not to let Chinook compete any more, but instead try to solve checkers. It was rated at 2814.
Chinook's program algorithm includes an opening book, a library of opening moves from games played by grandmasters; a deep search algorithm; a good move evaluation function; and an end-game database for all positions with eight pieces or fewer. The linear handcrafted evaluation function considers several features of the game board, including piece count, kings count, trapped kings, turn, runaway checkers (unimpeded path to be kinged) and other minor factors. All of Chinook's knowledge was programmed by its creators, rather than learned with artificial intelligence.
Jonathan Schaeffer wrote a book about Chinook called One Jump Ahead: Challenging Human Supremacy in Checkers, in 1997. An updated version of the book was published November 2008.
On May 24, 2003, Chinook completed its 10 piece database with 5 pieces on each side.
On August 2, 2004, the Chinook team announced that the tournament opening in English draughts called the White Doctor (10-14 22-18 12-16) has proven to be a draw.
On January 18, 2006, the Chinook team announced that the 09-13 21-17 05-09 opening has been proven to be a draw.
On April 18, 2006, the Chinook team announced that the 09-13 22-17 13-22 opening has been proven to be a draw.
On March 10, 2007, Jonathan Schaeffer announced (at the ACM SIGCSE 2007 conference) that a final solution to checkers was expected within 3-5 months.
On July 19, 2007, the journal Science published Schaeffer's team's article "Checkers Is Solved", presenting their proof that the best a player playing against Chinook can achieve is a draw.
Adapted from the Wikipedia article, Chinook (draughts player), http://en.wikipedia.org/wiki/Chinook_%28draughts_player%29, used under the GNU Free Documentation License.