A computer program that cannot lose at draughts will be unveiled today.
In a development described as a "truly significant advance in artificial intelligence", scientists have created software that plays a perfect game.
The achievement involved up to 200 computers running through 500 billion billion potential draughts positions over 18 years. Dr Jonathan Schaeffer and colleagues at the University of Alberta, Canada, announce the completion of the software called Chinook in a research paper published in the journal Science.
Dr Schaeffer began work on the project in 1989, with the aim of winning the world draughts championship.
With the help of human players, he created software to allow a computer to learn the best move through heuristics - learning through trial and error rather than by following set rules.
Dozens of computers were used in combination to run through the different possible sequences of moves.
The program lost in the world championship in 1992, but went on to win it in 1994 after refinements to the software. It remained undefeated until it "retired" in 1997. Dr Schaeffer and his colleagues continued to make changes until this year when they finally succeeded in making the program unbeatable.
Of course, if an opponent also plays perfectly, he or she could force a draw. Dr Jaap van den Herik, editor of International Computer Games Journal, said: "This is a tremendous achievement-a truly significant advance in artificial intelligence."
Dr Schaeffe said: "It's an exciting demonstration of the possibilities that software and hardware are now capable of achieving." Watch