Author: Ricardo Gibert
Date: 03:29:41 08/06/00
Go up one level in this thread
On August 05, 2000 at 06:47:04, Ricardo Gibert wrote: >On August 05, 2000 at 05:32:16, Colin Frayn wrote: > >>This position came up in a game I just played between ColChess (Development >>version) and Sjeng v7.1. >> >>[D]8/R7/8/8/7P/6P1/3k2K1/2q5 b - - >> >>ColChess, as Black, has to move, having just promoted a pawn to a queen, and >>then white played a rook move (Ra5-a7). >> >>This looks like it should be an easy win for black, but in the game ColChess >>just moved its pieces around aimlessly and drew by repetition. This annoyed me >>quite a bit so I tried this position at longer time controls and sure enough it >>still couldn't see anything. Then I tried it with Crafty and still nothing. >> >>Is this one of those positions where it's drawn and humans (if they're better >>than me) can see it easily but a computer can't? If so then I'd better fix >>ColChess' evaluation function before release so that it doesn't exchange off >>(from a stronger position it sac'd its rook to promote the pawn) > >In that case, I would guess it erred, since instead of Ra5-a7, the move Ra2+ >followed by Rf2 draws easily (at least). White can set up its Rook on f2, K on >h2 and the h-pawn on h3 when he would have an impregnable fortress. The white >Rook would then shuttle between f2 and any unguarded square on the f-file, then >back again to draw. Yikes! I have White moving in the wrong direction with his pawns. Nevermind 8-} > >You may have to resign yourself to the very distinct possibility that this is >not really fixable. "Fixing" such things can do more harm than good. Computers >are not good at recognizing fortresses. > >On the other hand, there may be another reason why your program should not have >played into this line that _is_ fixable. Why not post the position before the >sac and see how other programs handle it? > >As for the position you actually posted, my feeling is it should be drawn, but >do not ask me for proof. If you look up in a endgame book, you may find that >this type of position is drawn even without the h-pawn, since the remaining >g-pawn is probably close enough to the edge of the board for a draw. > >> >>I can (kind of) see why it might be drawn, but I'd appreciate input either way >>(maybe from those of you with 5-man TBs.) >> >>Cheers, >>Colin >> >>P.S. New version of ColChess is nearing completion. Still unsure whether it is >>actually stronger than the previous version but it's slightly faster and has >>some funky new features and a lot of code improvements and bugfixes.
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.