Author: Dave Gomboc
Date: 17:05:22 07/27/99
Go up one level in this thread
On July 27, 1999 at 19:51:17, KarinsDad wrote: >On July 27, 1999 at 19:28:17, Dave Gomboc wrote: > >[snip] >>>>>> >>>>>>White: Kg2, Qd5, pawns on b3, f2, g3, h4. >>>>>>Black: Kf6, Qe5, pawns on b4, g7, h7. >>>>>>White to move. >>>>>> >>>>>>I played 43. Qc6+, and my opponent blundered with 43...Qe6?? I went on to win >>>>>>the pawn ending after 44. Qxe6+ Kxe6 45. Kf3. >>>>> >[snip] >>> >>>43 ... Ke7 44. Qb7+ any 45. Qxb4 winning a pawn >>>43 ... Kf7 44. Qb7+ Qe7 (to protect the b pawn) 45. Qxe7 and black's king is >>>even further back than with what was played >>>43 ... Kf5 44. Qf3+ Kg6 45. Qg4+ any 46. Qxb4 >>>43 ... Kf5 44. Qf3+ Ke6 45. Qb3+ any 46. Qxb4 >>> >>>> >[snip] >>> >>>I don't see Crafty not picking a swindle move in a lost game as being inferior. >>>That's all. >> >>If I back up in the game, Crafty also picks a bad move earlier, ...Qe5, based on >>the incorrect PV that is given when analyzing the position that I posted. Bad >>assessments are costly, whether they affect the PV in the particular position or >>not, because there'll be a different position where it _does_ affect the PV. >> >>It's not a matter of swindling at all. It's a matter of playing moves that make >>the opponent's task difficult. This is _extremely_ important. See Jose's post >>for more on that. If Crafty knew (as Bob says it will soon) that the majority >>will create an outside passer, it would have preferred to drop its b-pawn and >>make White work harder for the win. Crafty may also not have played ...Qe5, >>leading to the position that I posted. >> > >Staying with the original position you posted (and not some earlier move), if I >look at the 4 variations above (which are the only ones I see off the top of my >head other than the one Crafty picked), it appears that one leads to black's >king being backed up an additional square and the rest lead to black losing a >pawn and no apparent way to force perpetual check or to win the pawn back. If >gaining the pawn was difficult to defend, then I may agree with you. > >Granted, for a human, the ones that lead to white winning the pawn are more >complex positions due to the checks. For a computer, this is probably not true >(at least I would hope not when searching 12+ ply down). > >So, a human may allow the loss of a pawn in order to get the checks in, but a >computer would try to hang onto the pawn if it saw no way to force something by >losing it. > >Your point is well taken, but this is a lousy example (IMO) and Crafty played as >good as the position allowed. > >KarinsDad :) It's a lousy example in the sense that other alternatives lost anyway. It's still a good example for showing that what it chose lost easily. But see my reply to myself :) that shows Crafty definately losing a position that may not even be a win... or a torturously long win, if it is one. Dave
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