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How Chess Computers Work

If you have ever watched a person first learning to play chess, you know that a human chess player starts with very limited abilities. Once a player understands the basic rules that control each piece, he or she can "play" chess. However, the new player is not very good. Each early defeat comes as something of a surprise -- "Oh, I didn't think about that!" or "I didn't see that coming!" are common exclamations.

The human mind absorbs these experiences, stores away different board configurations, discovers certain tricks and ploys, and generally soaks up the nuances of the game one move at a time. As the level of skill develops, the player will often read books to discover patterns of play used by the best players. Strategies and tactics develop to guide the player through each game.

For a human being, therefore, the game of chess involves a great deal of high-level abstract thought -- visual pattern matching to recall board positions, rules and guidelines, conscious thought and even psychology.

Computers do none of this.

Chess seems like a distinctly human activity, requiring intelligence and thought, so how can a computer possibly do it?

In this article, we will take a look at this question. What you will find is that computers don't really "play" chess like people do. A computer that is playing chess is not "thinking." Instead, it is calculating through a set of formulas that cause it to make good moves. As computers have gotten faster and faster, the quality of these calculated moves has gotten better and better. Computer chess calculators are now the best chess players on the planet, even though they do it totally blindly.

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