Author: Vincent Diepeveen
Date: 16:32:18 10/07/00
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On October 07, 2000 at 15:16:17, Peter McKenzie wrote: >The position where the solution is most in doubt: > >[D]2k2K2/8/pp6/2p5/2P5/PP6/8/8 w - - > >The authors say that after 1.Ke8 Kc7 2.Ke7, black draws by 2...b5 with a >stalemate motif after 3.Ke6 b4 4.a4 Kb6. nice motif for humans. peanut for the computer to see. however, after 1.a4 i get a 0.00 score from diep initially, now there are sure some bugs in this version, as i'm busy rewriting its hashing to 64 bits (which asks for bugs of course), but 0.00 is pretty hard. it is basically doubting between 0.50 and 0.00 on most plies. where the stalemate position is 50 moves of shuffling around with king and score +1.31. this version not showing +3.x scores weirdly. what is the win with a4 which i'm missing? and 20 plies of search too, which is hard to believe in this position. with all 3 vs 2 egtb attached and 20 plies of search with the white king already penetrated i either expect to see +mateXX or see many pawns go or see draw score if it's a draw. Now i get a slight draw score depending upon depth it is 0.00 or +0.50 for white. That's not very convincing. >Of course white can vary, and they quote: 4.axb4 cxb4 5.Kd5 a5 6.Kc5 a4= > >Or: 2.a4 b5 which is supposed to be drawn too. >I haven't checked these lines thoroughly, but quickly playing some of them vs my >program suggests they are probably correct. Certainly its possible there is a >mistake though. > >The other controversial positon: > >[D]8/1k6/p4p2/2p2P2/p1P2P2/2P5/P1K5/8 w - - > >Kc1 is analysed using the 'theory of corresponding squares', something I don't >really understand :-) I haven't analysed this one at all, I will just quote the >main variation: i have wasted a full evening to go to a meeting where the writers about the 'corresponding square' theory were there. it's all big nonsense. the problem is to figure out what the corresponding squares are. it's like saying: "find best move M and play perfect chess". Now the problem is to find move M. So is the problem to find the corresponding squares. There is no algorithm for it at all. After wasting hours of talk to the authors who themselves aren't strong chessplayers at all, they couldn't give any algorithm for it, and it all appeared to come down to how well you can define squares as being the corresponding square! >1.Kc1! Kc7 2.Kd1! Kd7 3.Ke1 Kc7 4.Kf2 Kd8 5.Ke2 Ke8 6.Kd3 Kd7 7.Ke3 Kd6 8.Ke4 >"(forcing the pawn to advance)" a3 9.Kd3 a5 10.Kc2! a4 "The posiiton on the >Q-side is blocked; a quadratic system with non-ambiguous rear (711) now >operates." Go figure! 11.Kc2! Ke7 12.Kd3 Kc6 13.Ke2 Kd6 14.Kf2 Kd7 15.Ke3 Ke7 >16.Kf3 and wins that's 16 moves. I'm searching 40 plies. that's 20 moves. So i see 4 moves deeper as this. Also i have made afew moves and then also searched 40 plies. that's like 23 ply in the diagram position. So obviously this trick isn't the problem here! >I didn't play thru. that variation, but clearly its at least 31ply and white >hasn't even captured a pawn yet! Let me see, finished with white K on f3, so it >needs another 3 moves at the very least to capture c5 so this problem looks like >it is at the VERY least 34ply deep and probably more. I searched if i count the moves made first with it 44 plies or something and don't see a win at all. >cheers, >Peter
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