Fritz’s ‘parent’ company, X3D Technologies, has been providing on-line coverage of the match with an excellent website offering live commentary and in-depth analysis.
Kasparov’s victory with the white pieces in the third game is a textbook example of how to beat a computer at chess. The postgame analysis reveals not only the extent of Kasparov’s preparation for the match but also the limitations of computer ‘thinking’.
This useless-looking move [by Kasparov] confused most of the commentators, but to anyone with extensive anti-computer chess experience it makes perfect sense. The rook protects the f2 pawn, a potential weak spot, but why would you protect something that isn't being attacked?
The reason goes into how computers think. Its brute force calculation can only go so deep, even with four super-fast processors. Black's only possible source of counterplay in this position is to push its f-pawn and open up an attack against the area around the white king, f2 in particular.
If X3D Fritz's search, usually running 12-20 half-moves deep, ever reaches a position in which it sees success in such an attack it will put such a plan in motion. On the other hand, if it cannot reach a favorable position in its searches it will never play the initial moves required. With the rook on b2 protecting f2 already, the potential weakness of that critical square is somewhat hidden from the computer's search.
X3D Fritz can't just play it anyway like a human would, knowing that everything else is useless. A machine has to receive a positive evaluation from its search to play a move and always plays the move that gives it the best evaluation. Since X3D Fritz sees no danger here for itself it is content to play moves that do nothing, but don't cause any negative effect either. It twiddles its virtual reality thumbs. Any human would say, "I have to do SOMETHING."
