Author: Dave Gomboc
Date: 16:28:17 07/27/99
Go up one level in this thread
On July 27, 1999 at 18:50:08, KarinsDad wrote: >On July 27, 1999 at 18:25:20, Dave Gomboc wrote: > >>On July 27, 1999 at 17:28:48, KarinsDad wrote: >> >>>On July 27, 1999 at 14:07:22, Dave Gomboc wrote: >>> >>>>Last night I reached the following position as White in the blitz portion of a >>>>game/30: >>>> >>>>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. >>> >>>Why was this a blunder? There are no good moves. What better move did black >>>have? >>> >>>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 ... Kf4 44. Qf3+ Kg3 45. Qg4+ any 46. Qxb4 >>>43 ... Kf4 44. Qf3+ Kg4 45. h4+ Kg3 46. Qg4+ any 47. Qxb4 >>>43 ... Kf4 44. Qf3+ Kg4 45. h4+ Kh3 46. g4 and black cannot take the b pawn or >>>47. Qf4+ Kg3 48. h5++ or Kh4 48. Qg5++ >>>43 ... Kg4 44. h4+ and a variety of other moves which lead to the same capturing >>>of the b pawn or mate with the same themes as above >>> >>>And eventually, no matter how black plays, once white wins the b pawn, all white >>>has to do is place the queen on b7 and push the b pawn. If black tries to check >>>white first, white plays Kh3, interposes his queen on any other check, puts his >>>king back on g2, eventually plays Qf3, and can push b3 to protect the b pawn. It >>>will be REAL hard for black to prevent white from trading queens and having a >>>passed pawn. >>> >>>This seems lost no matter what, so how exactly did black blunder here? Not >>>trading queens does not delay the inevitable much, if at all. >>> >>>KarinsDad :) >> >>Some of your variations don't make sense. You must have reset your board to the >>wrong position. Specifically, White has a pawn on h4, and some lines you have >>Black playing ...Kg4 and White playing h4+. > >My apologies. I had the pawn on h2. It doesn't change much except to prevent the >Kg5 line. I also screwed up and keep placing the king on f4, g4 and g3 instead >of f5, g5, and g6 (I have a type of dyslexia when I type variations from my >head). > >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 > >> >>Your general argument is that White can pick up the b-pawn, and this is true. >>(That had been my plan until I was presented with an easier win.) After White >>grabs the b-pawn, he needs to cover b3 and f2 without allowing perpetual check, >>and slowly work his b-pawn forward. You're right in saying that this also wins. >> It's not really so much that it takes longer in the terms of "number of moves", >>it's just that it takes thought. In the game as played, White was able to play >>on auto-pilot. The win is clear, and Black has zero counterplay. This was >>important: we only had about a minute or so each at that point. >> >>"Blunder" is how I felt about allowing the queen exchange as the game was being >>played. I'll agree that that is too strong a word when there's plenty of time >>to look at the position, though. Part of my impression was because Black _had_ >>his king in the corner earlier, but instead of playing h6, or g6 and h5, he went >>and played it into the middle. In the game he had time to go back and hide, but >>by the time we reached the position that I posted, it was already too late for >>that. > >The point was that Black is lost. Crafty realized it was lost and saw Qe6 as the >best of a series of lousy moves, most of which lose an additional pawn. Saving >that pawn and preventing perpetual checks is very easy for a computer, so I did >not understand the term blunder when it seems the best move, unless you want to >try to swindle a human into a draw or you are playing against a human with low >time. > >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. >> >>The main point of my post was that Crafty was misevaluating the position after >>the exchange of queens. The static eval is about 1.3, and it probably needs to >>be something like 4 (higher than an extra minor piece, anyway.) The tricky part >>to doing that is to make sure you are not assigning scores like that to pawn >>endings that aren't clearly winning at the same time. >> >>Dave > >KarinsDad :) Dave
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