Author: Uri Blass
Date: 04:30:45 03/07/02
Go up one level in this thread
On March 07, 2002 at 03:50:04, Andreas Stabel wrote: >On March 05, 2002 at 08:12:17, Albert Silver wrote: > >>On March 05, 2002 at 06:36:58, Ed Schröder wrote: >> >>>On March 05, 2002 at 05:15:38, Uri Blass wrote: >>> >>>>Yace also likes f5 and has Rh3 in the main line so it seems that finding a >>>>better move than Rh3 is not easy. >>>> >>>>The question is if Rh3 is winning. >>> >>>I don't know, a further investigation is needed IMO. Rebel gives a +2.30 score >>>for Rh3 after 15 plies but probably most of that is coming from eval. >>> >>>00:00:01.5 1,34 7 416116 Rh3 Kf7 exf5 Bxb3 Qxg6+ Ke7 Rh7+ Rf7 >>>00:00:02.5 1,34 8 948561 Rh3 Kf7 exf5 Bxb3 Qxg6+ Ke7 Rh7+ Rf7 >>>00:00:04.9 1,34 9 2379413 Rh3 Kf7 exf5 Bxb3 Qxg6+ Ke7 Rh7+ Rf7 >>>00:00:08.7 2,22 10 5564762 Rh3 Kf7 exf5 Bxb3 Qxg6+ Ke7 Rh7+ Rf7 >>>00:00:16.6 2,10 11 12107255 Rh3 Kf7 exf5 Bxb3 Qxg6+ Ke7 Qg5+ Rf6 >>>00:00:42.6 1,78 12 31920754 Rh3 Kf7 Qh7+ Kf6 Qh4+ Kg7 Bxe6 Qxe6 >>>00:02:02.0 1,62 13 95158047 Rh3 Kf7 Qh7+ Kf6 Qh4+ Kf7 exf5 Bxb3 >>>00:06:49.0 2,30 14 322198950 Rh3 Kf7 Qh7+ Kf6 Qh4+ Kg7 Bxe6 >>>00:14:38.6 2,30 15 688286326 Rh3 Kf7 Qh7+ Kf6 Qh4+ Kg7 Qh7+ Kf6 >>> >>> >>> >>>>If Rh3 is not winning then it means that Rebel found the right move for the >>>>wrong reasons >>> >>>That's a popular statement in this forum, I once had similar thoughts but >>>changed my mind. It does not matter if Nxg6! is played by eval or search, the >>>only thing that matters is playing the good move. >> >>Yes and no. Suppose it finds Nxg6 but yields a draw score with a perpetual check >>in its main line. Nxg6 is a winning move, so if Rebel were to play it thinking >>it drew, how do you know it won't content itself with the draw? Would you >>consider it found Nxg6, the _winning_ move, just because it played it? That for >>me is the crucial question. I often see programs find a very delicate sacrifice >>but with a draw score, and even by feeding them the responses, they do not win >>the game. So what then? >> >>Uri's comment here is relevant also because it isn't shown why Rebel immediately >>sacs the bishop back with Bc1. No doubt this is the best reply for Black, but >>did Rebel do this because it saw a genuine follow-up for White if f5 was played, >>or did it see a ghost? >> >>As to the comment on Rh3, it wasn't so much a complaint (I saw the smiley BTW) >>as comment on my challenge: find the strongest continuation. In this case, let's >>broaden this to find the best continuation after 25.Nxg6 hxg6 26.Qh6 Be6 27.Rd3 >>f5. >> >>The strongest continuation BTW isn't 28.Rh3, it is 28.Rg3! Rf6 29.Rh3 Kf7 >>30.Qh7+ Kf8 31.exf5! >> >> Albert > >I let crafty run over night on the position after 28. Rg3: >18-> 946:29 0.46 4. ... Rf6 5. Rh3 Kf7 6. Qh7+ Kf8 7. > exf5 Bxb3 8. axb3 Rxf5 9. b4 Rh5 10. > Bc5+ Ne7 11. Rf3+ Rf5 12. Rxf5+ gxf5 > 13. Qxf5+ Qf7 14. Qxe5 Qh7 15. g4 Bb2 > 16. f4 Qb1+ 17. Kf2 > >It doesn't seem very convincing to me. > >Best regards >Andreas Stabel You do not use the computer correctly a long line was posted it is easy to find that 4...Rf6 and 5...Kf7 and 6...Kf8 is forced in this line because the evaluation of the next best move is more than +4 for white. The first move that is not obviously forced is Bxb3 so it is better if you give the computer to analyze only the position after 7.exf5 in that position black has only few alternatives not to lose the game in one move 1)Bxb3 axb3 is the typical computer line 2)Rxf5 Qh8+ Ke7 Qxe8+ Kxe8 may be the best for black but white has a clear advantage here. 3)gxf5 Rg3 Bf7 Bxf7 Qxf7 Qh8+ Ke7 Rg7 Qxg7 Qxg7+ Rf7 Qg8 is more than 2.5 for white 4)Bc4 Be3 Qd8 Qh8+ Ke7 Qg7+ Rf7 Bg5+ Kd7 Qxf7+ is 2.54 for white based on Crafty18.12 and black has no better alternative in this line after Bc4 5)Bf7 fxg6 is more than +3 for white let analyze after Bxb3 axb3 the alternatives to consider for black are 1)Ne7 Qh8+ Ng8 b4 is winning for white your main line 2)Rxf5 b4 Rh5 Bc5+ Ne7 Rf3+ Rf5 Rd3! is winning for white(the move that crafty did not see in your line) 3)gxf5 b4 Qe6 Bc5+ is winning for white 4)e4 b4 winning for white Uri
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