Author: Ed Schröder
Date: 21:31:36 04/16/00
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On April 16, 2000 at 13:37:24, Robert Hyatt wrote: >On April 16, 2000 at 12:23:08, Ed Schröder wrote: > >>On April 16, 2000 at 12:10:41, Fernando Villegas wrote: >> >>>I think Rebel performed a really great show. After examination the game appears >>>fullo of tricks and traps -positionally kind- that very easily could put in the >>>wrong path more than a kown top chess program in SSDF list. My congrats for Ed, >>>that clearly seems to have "pasted" some of the holes in the tactical arena of >>>Rebel. >>>Fernando >> >>Thank you Fernando. I was quite nervous during the ending when I saw >>the white king moving to the queen side to hunt for the two weak >>black pawns on c6 and a6 leaving its own king undevelopped. But the >>wall Rebel created with Nb7 did the trick and according Smyslov himself >>there was no win. Well.. during the game I was not convinced of that as >>the Smyslov position looked real promising. But these monsters are tough >>defenders (most of the time). When I saw Rebel showing senseless moves >>in its main-variation (Bg7 / Bh8 / Bg7) I relaxed as this was a sign >>for me there was no progress for white. I am very happy with the draw. >> >>Not to speak about the Israel League, so far 4½ out of 5. What is there >>left to wish? Nothing... >> >>Ed > > >I thought you defended as well as anyone/anything could. The only thing I >didn't like was to see Rebel exchange into what was almost certainly a lost >ending (white with a queenside majority, black king on the other side of the >board.) Hard to say if it was really lost or not, as Smyslov made more than >one move that Crafty thought was wrong. Of course Crafty could have been >wrong instead, so that is not conclusive. But clearly there was no way for >white to lose, and no way for black to win, so why go for such a pawn >structure??? > >IE defending great is nice, but I would rather be working hard for a win, >with a possible draw option, rather than working hard for a draw, with a >very possible loss option... > >What caused Rebel to go for that setup in the first place? IE this is why I >have been fiddling with the pawn majority / candidate passed pawn code for so >long now... If you get that position vs a GM in blitz, you almost certainly >lose it. And if you let them get it, they will, over and over. There are >way too many different examples of that 3 vs 2 queenside where white wins >trivially, to take a chance on reaching it, IMHO. And if you get tricked into >reaching it, keeping heavy pieces on the board is the right answer. Trading >helps the majority side... And what did you have in mind as the right value of the bonus (penalty) for the pawn majority on the queen-side for the positions in question? The queen and rook exchanges comes to mind. It's tricky tricky IMO as evaluations for center control, pawn structure and mobility are more dominating most of the time in a game. More: such a bonus for majority must be lower than the value of a passed pawn otherwise your program will never force the passer and even will avoid to make a passer by all means resulting in stupid moves. I am not saying you are not right I am just curious how you evaluate such difficult cases in the right way. Another side effect of pawn majorities: if the bonus is too high your program could make stupid defense moves to avoid trading material where it really should trade. Strangely enough it was Rebel who got a passer on the board as first one. Even better, Smyslov never had one :) Ed
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