
Chess as the computer sees it
It's interesting to try to see the game as the computer does. Broadly speaking, the computer evaluates all possible moves for a set depth and then assigns a value to the resulting positions. It decides that the move giving the highest minimum value at the ends of the analysis tree is the best move. If you look at the point scores assigned by a chess program as it analyses a finished game, you will see that no move ever increases the score for the side moving. When Black moves, whatever he does, the best possible outcome is that Black maintains his position. After he moves, Black's score can remain equal or almost the same (good move), go down by 0.1 (inaccuracy), go down by 0.2 to 1.0 (mistake), or go down by 2 or more points (blunder).
Does this mean there is no such thing as a move that improves your position? From the computer's point of view, the answer is "yes". In its view, the only moves that improve your position are inferior moves made by your opponent. This is at odds with our normal perception of chess, ie that people make "strong" moves that change a position from equal to superior, or even "winning", for the side making the move. These are the moves that attract exclamation marks from human annotators. So who is right, the silicon monster, or the carbon-based life-form?
I guess the answer depends on how you look at chess. If you look at chess as a logical puzzle to be solved then the computer is right. If you look at it as a battle between two fallible and creative human beings, each striving to find the other's weaknesses, then the computer is wrong.
Consider also that the computer will never lay a trap, as human players often try to do. That is, it will never lay a trap if the opponent can make a response move that improves his position even slightly. Unlike a human, the computer is incapable of seeing that the right response move can be hard to see for its opponent. As most people know, chess is not just a logical game - there is an element of psychology. That element is totally absent from the computer's purview and constitutes one of the few advantages a human has over a computer. Note, however, that this only applies to playing humans - if you are playing against an electronic brain then forget about trying to use psychology!