Author: Uri Blass
Date: 11:56:56 04/28/02
Go up one level in this thread
On April 28, 2002 at 14:35:41, Roy Eassa wrote: >On April 28, 2002 at 14:17:54, John Merlino wrote: > >>On April 28, 2002 at 01:19:27, Uri Blass wrote: >> >>>On April 27, 2002 at 18:41:28, John Merlino wrote: >>> >>>>On April 27, 2002 at 18:12:27, Uri Blass wrote: >>>> >>>>>The following position is from my last game >>>>> >>>>>[D]6k1/RR4p1/5p1p/4p3/8/P7/4rrPP/3K4 b - - 0 31 >>>>> >>>>>I played 31...Rxg2 and after 32.a4 Ra2 my opponent resigned. >>>>> >>>>> >>>>> >>>>>After the game he said that he needed one more tempo. >>>>> >>>>>I said that I was lucky because I saw the idea of Rxg7+ that almost win the game >>>>>only after I played 31...Rxg2. >>>>> >>>>>I played 31...Rxg2 fast because the move seemed to be almost forced(I did not >>>>>like the idea of Rd2+ Kc1 and the idea of Ra2 with the double mate threat is >>>>>gone) >>>>> >>>>>I also said in the anlaysis that the best was still 32.Rxg7+ Rxg7 33.Ra8+ >>>>>inspite of the fact that white is losing after 33...Kf7 34.Kxe2 Rg2+ because in >>>>>the worst case black will need to sacrifice the rook for the a pawn when the >>>>>black passed pawns are going to be srtronger than the rook. >>>>> >>>>> >>>>>I find that some top programs cannot find 31...Rxg2 >>>>>for black because they do not evaluate correctly the pawn endgame. >>>>> >>>>> >>>>>Uri >>>> >>>>It takes Chessmaster 9000 (pre-Beta) 2:05 on a PIII-600 to see Rxg2, but about a >>>>minute later it discards it for Rd2+ (which turns out to be two checking moves >>>>to force the White King farther away from the Black pawns BEFORE taking on g2): >>> >>>The problem is that the line that chessmaster suggests is not forced. >>> >>>31...Rd2+ 32.Kc1 Rc2+ 33.Kb1 Rxg2 34.Rxg7+ is not a forced line from white point >>>of view. >>> >>>White can choose 32.Ke1 >>> >>>Uri >> >>Well, maybe not "forced", but, according to CM, 31...Rd2+ 32.Ke1 leads to this >>(with an eval that is instantly about 1.50 worse for White than if 32.Kc1): >> >>Time Depth Score Positions Moves >>0:00 1/3 -2.51 2176 32...Rfe2+ 33.Kf1 Rxg2 34.a4 Rgf2+ >> 35.Kg1 >>0:00 1/4 -2.49 6886 32...Rfe2+ 33.Kf1 Rxg2 34.a4 Rdf2+ >> 35.Ke1 Re2+ 36.Kd1 >>0:00 2/5 -2.42 32451 32...Rfe2+ 33.Kf1 Rxg2 34.a4 Rdf2+ >> 35.Ke1 Ra2 36.Kf1 f5 37.a5 Rgf2+ >> 38.Ke1 >>0:01 3/6 -2.46 79710 32...Rfe2+ 33.Kf1 Rxg2 34.a4 Rdf2+ >> 35.Ke1 Ra2 36.Kf1 Kh8 37.h4 Rgf2+ >> 38.Ke1 Rfe2+ 39.Kf1 >>0:03 4/7 -2.50 269671 32...Rfe2+ 33.Kf1 Rxg2 34.a4 Rdf2+ >> 35.Ke1 Ra2 36.Kf1 Rg4 37.h3 Rf4+ >> 38.Ke1 Re4+ 39.Kf1 >>0:08 5/8 -2.54 756383 32...Rfe2+ 33.Kf1 Rxg2 34.a4 Rdf2+ >> 35.Ke1 Ra2 36.Kf1 Kh8 37.h4 Rgc2 >> 38.Rb1 Kh7 39.h5 >>0:27 6/9 -2.44 2437336 32...Rfe2+ 33.Kf1 Rxg2 34.a4 Rdf2+ >> 35.Ke1 Ra2 36.Kf1 Kh8 37.Ra8+ Kh7 >> 38.Raa7 Raf2+ 39.Ke1 Rc2 40.Kf1 >> Rg4 41.h3 Rf4+ 42.Ke1 >>1:26 7/10 -2.71 8085064 32...Rfe2+ 33.Kf1 Rxg2 34.a4 Rdf2+ >> 35.Ke1 Ra2 36.Kf1 Kh8 37.Ra8+ Kh7 >> 38.Raa7 e4 39.Re7 e3 40.Rxe3 Rxh2 >> 41.Kg1 Kg6 >>4:38 8/11 -2.81 26452346 32...Rfe2+ 33.Kf1 Rxg2 34.a4 Rdf2+ >> 35.Ke1 Ra2 36.Kf1 Kh8 37.Ra8+ Kh7 >> 38.Raa7 h5 39.Rd7 Rgc2 40.Ke1 Kg6 >> 41.a5 Kf5 >> >>It probably all leads to the same loss, anyway.... >> >>jm > > >It DOES matter, though, because it affects what is the "best" move. It seems >that it is indeed best to do the two checking moves first (pushing the king >away), THEN take the pawn. I.e., Rxg2 is NOT the best first move. I disagree. I do not see why pusing the king away is better. It only delay the win. Rxg2 immediatly force Rxg7+ and after Rxg7 a lot of programs do not know to evaluate correctly the pawn endgame. Their main line before changing their mind from Rxg2 is not Rxg2 Rxg7+ Rxg7 Ra8+ but Rxg2 Rxg7+ Rxg7 Rxg7+?? Uri
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