Author: Robert Hyatt
Date: 08:15:23 07/15/04
Go up one level in this thread
On July 15, 2004 at 03:51:15, Ed Schröder wrote: >On July 14, 2004 at 22:52:51, Robert Hyatt wrote: > >>On July 14, 2004 at 10:48:09, Peter Berger wrote: >> >>>On July 14, 2004 at 09:59:06, Matthew Hull wrote: >>> >>>>On July 14, 2004 at 07:53:07, Ed Schröder wrote: >>>> >>>>>On July 14, 2004 at 01:50:03, Russell Reagan wrote: >>>>> >>>>>>On July 12, 2004 at 03:51:44, Ed Schröder wrote: >>>>>> >>>>>>>The question here is how Crafty being down a pawn, also facing 3 connected >>>>>>>passers (h2,g2,f2) evaluates this position. Did 42..a5! show a possitive score >>>>>>>for Crafty then hat off for Crafty. Did 42..a5! show a < -1.xx or even lower >>>>>>>then I would say Crafty indeed was lucky. >>>>>> >>>>>>I look at it from a different perspective. Crafty was the better engine this >>>>>>game. Dan Heisman says it better than I could. >>>>>> >>>>>>http://www.chesscafe.com/text/real.txt >>>>>> >>>>>>"A Chain is Only As Strong As Its Weakest Link >>>>>>The best way to introduce the second part of my explanation is to >>>>>>make an analogy. Suppose you build a home where the temperature >>>>>>is -20 degrees outside. You decide on a one-room home with four >>>>>>walls, a roof, a floor, and a heater. You decide to save a little time >>>>>>and material by finishing the four walls, the floor, and half the roof, >>>>>>but the other half you leave open. Even though you have completed >>>>>>over 90% of the structure, the temperature inside your home will >>>>>>still be about -20 degrees with half your roof open. If you want >>>>>>your inside heater to be effective, you have to enclose all of your >>>>>>home. >>>>>> >>>>>>The cold home analogy is similar to what happens when you play >>>>>>Real chess for 90% of your moves, but not for the other 10%. You >>>>>>think you are a good player, but weaker players beat you when you >>>>>>let down your guard for that 10%. In order to be a good player, you >>>>>>have to at least try to play correctly on every move, not just most of >>>>>>them. Consistency is important: remember that your chain of >>>>>>moves, in many cases, is only as strong as the weakest link." >>>>>> >>>>>>Crafty may have been outplayed for most of the game, but it was more consistent >>>>>>than Falcon, so it ended up the better engine that game. >>>>> >>>>> >>>>>I disagree with the comparison. In computer chess it sometimes happens a >>>>>position being so full of dynamics both computers impossibly can't see (predict) >>>>>the outcome neither by eval nor by search. In such a case luck moves in. I think >>>>>42..a5! is such a case. >>>>> >>>>>It's like in soccer, 2 equal teams, the ball by one unfortunate clutch coming >>>>>right for the foot of the opponent and BANG, you lose. Nobody is to blame. >>>>> >>>>>In human chess it is different, the human player can always be blamed for not >>>>>seeing the strategic consequences. It's different with computer chess since >>>>>strategic understanding hardly is to program and still is an unexplored area. >>>>> >>>>>To demonstrate my point, put the 42..a5! position in any program, let it think >>>>>for 1 ply and I predict no program will report a plus score for black. >>>> >>>> >>>>Look. Basically white got the advantage and couldn't capitalize. This happens >>>>often in human and computer tournaments. If I spoil my advantage, I can expect >>>>to be punished. The fault is with white, who simply did not know how to finish. >>>> How many times did Boris say in favor of white, "This game is over"? Many >>>>times. White simply dropped the ball. There was no luck. Only failure. >>>> >>>>"Crafty was lucky" is a classic cop-out excuse, just like someone we all know. >>>>Why follow in _that_ person's footsteps? >>>> >>> >>>I assume this is a misunderstanding. Ed pointed out that both engines had no >>>clue how to evaluate the position after 42. ..a5 properly and saw white with >>>winning score. In this case it is clearly luck but not superior knowledge that >>>black was doing just fine. >>> >>>This doesn't put any blame on Crafty that did a fine job finding the correct >>>moves nevertheless, but it would have liked to play into this position with the >>>white pieces too, so luck is quite appropriate. What's so bad about luck anway? >>> >>>Peter > > >>This is missing the main issue. After a5, black is _not_ winning. > >Correct. > > >>White is winning here. > >No, it is a draw and that's why Crafty was lucky in this game because both >Crafty and Falcon had no clue, they both still evaluated the position as very >favorable for white. True? > >42..a5! forced the draw, 43.Ra8 is only the quickest way to that draw. The fact >Falcon did not took the draw is a matter of a different magnitude, something >that can be seen by evaluation, te real error is not 43.Ra8 but 46.Ra5? while >46.Ra6 would have ensured the draw instantly. > > > >>If he advances the h-pawn, black is most likely going to lose. > >No, much too risky. Just look at the white rook and how the thing is isolated, >it can't go anywhere to stop the dangerous a-passer. > > > > >>The key issue is not that black played a5 and was winning without knowing, black >>knew this game was nearly lost, and played the only reasonable move, namely a5 >>to make a passed pawn and create counter-play. Black self-immolated with Ra8 >>and at that instant, the score swung from +2 to nearly zero and dropping every >>iteration. It took less than 15 seconds to see that white had screwed up badly. > >42..a5! was an excellent move and so was 46..Kb6!! going for a win instead of a >draw. Very nice play by Crafty. > > > >>So this isn't an issue of black playing a5 without a clue, it had a _good_ clue >>of the best plan to proceed, but white failed to play properly and the game was >>lost. Not by misunderstanding by black. And no, had crafty been playing white >>it would _not_ have lost, because it had seen the correct white move rather than >> what was actually played in the game. >> >>The point here is that 42. ... a5 does _not_ get an exclam (!). 43. Ra8?? gets >>the slam (??). Crafty had nothing to do with Ra8. > >Analyse again, 43.Ra8 is okay, 46.Ra5?? is Falcon's losing mistake. And you sir >were a bit lucky moving from a lost middle-game position into a drawish ending >which neither of you evaluated right :) > >My best, > >Ed If you mean I was a bit lucky because my opponent blundered, I happen to agree. Luck _always_ is present in these events. I've seen it too many times. I haven't studied the game enough to say yet that a5 is a forced draw. What I can say is that Crafty certainly evaluates the position after a5 far better for white than the position after Ra8. I'm not yet convinced whites three connected passed pawns can't overwhelm the rook...
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