What a way to Win

[AdminX]

For more on the Zappa vs Rybka match see the write up just posted on Chess Vibes called "What A Way To Win":

http://www.chessvibes.com/?p=1284

During during the World Championship in Mexico, the computer match Rybka-Zappa was played. In the fourth game something happened that made me lose interest in this match (and actually in computer-computer matches in general).

"It’s not that I want to treat Zappa’s victory with disregard – beating Rybka in a match is a fine achievement – but what happened in game 4 resulted in some scepticism on my part about games between computers."

Quoting Peter from article

[Ovyron]

"Get the point, people! The operators won this game, not the program."
~Terrier

I don't get it, I think that engines should always play to the end, I even have wasted hours by watching games that were dead draws, or to the end when one engine has a sure win, just because sometimes the draws aren't draws, engines throw away sure wins or even turn wins into loses.

Had the operators stayed quiet the whole game, it would still had been 1-0 for Zappa. So, the operators' actions are irrelevant, and what should be being discussed is how Rybka threw the draw in such an important match (it cost them $5000).

[Mike S.]

Yes... Rybka had an evaluation problem, being too optimistic. Although, after reconsidering it I think it may be difficult to generalize. When the problem began, Rybka had Q+5P versus RRBP which involved passed pawns for Rybka. But maybe the real reason was the evaluation of the situation with QPP (connected passers) vs. RRB which arose shortly after the wrong pawn sacs.

Btw. Zappa's eval was also in favour of White after the first sacrifice, 109. h6 {(Df4) 33} Rxh6 {0.73/20 35}.

[CRoberson]

The operators did not win the game - the Zappa operators chose
to let Rybka lose.

Also, the article is incorrect on two programming points. In order for
a program to drop a pawn to keep the game going beyond the 50
move rule, the eval value must be greater than a pawn not greater
than 0.00.

But, it was a risk, Zappa could have made a mistake after that point.
Bugs can happen.