Wednesday, October 3, 2007

Perfect Checkers

Science marches on. First the computers solved Connect Four, now they have solved checkers. Here is the full, and very readable, abstract from a paper titled "Checkers is Solved" from Science:

"The game of checkers has roughly 500 billion billion possible positions (5 × 10^20). The task of solving the game, determining the final result in a game with no mistakes made by either player, is daunting. Since 1989, almost continuously, dozens of computers have been working on solving
checkers, applying state-of-the-art artificial intelligence techniques to the proving process. This paper announces that checkers is now solved: Perfect play by both sides leads to a draw. This is the most challenging popular game to be solved to date, roughly one million times as complex as Connect Four. Artificial intelligence technology has been used to generate strong heuristic-based game-playing programs, such as Deep Blue for chess. Solving a game takes this to the next level by replacing the heuristics with perfection."

As someone who never was a big fan of checkers, I am most impressed by the sheer effort put into exploring the computational space for this game, and I am also impressed by the clarity of the writing for this paper. They even translate the scientific notion into more colloquial terms ("billion billion", sounding like Carl Sagan on "repeat"). Also note the way "perfect" is used. It carries the connotation of "complete," just like in the Sermon on the Mount ("be ye perfect as your Father in heaven is perfect").

Of course, the ultimate question always is: I wonder where you get grant money for things like this? (The answer is to move to Canada: Canada’s Natural Sciences and Engineering Research Council (NSERC), Alberta’s Informatics Circle of Research Excellence (iCORE), and the Canada Foundation for Innovation funded this study.)

And how long until we solve perfect chess?

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