Author: Uri Blass
Date: 07:29:47 03/05/02
Go up one level in this thread
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! Yace can learn +1.20 for white from this line (I was too lazy to teach it more) I added 31...Bxb3 32.axb3 Ne7 33.Qh8+ Ng8 34.b4 or 32...Rxf5 33.b4 +1.20 is still not enough to convince yace to play Bc1 because the score after Bc1 is 1.41 for white. New position [D]4qrk1/8/pBn1b1pQ/1p2pp2/4P3/bBPR4/P4PPP/6K1 w - f6 0 1 Analysis by Yace 0.99.56: 4.exf5 Bxb3 5.axb3 Rxf5 -+ (-1.69) Depth: 1 00:00:00 4.Rg3 Rf6 5.Rh3 Kf7 6.Qh7+ Kf8 7.exf5 Bxb3 8.axb3 gxf5 9.Rg3 Qe6 10.b4 Ke8 11.Rg8+ Rf8 12.Qh5+ Qf7 13.Rxf8+ Kxf8 14.Qh6+ Ke8 15.Qxc6+ Qd7 16.Qg6+ Qf7 17.Qd6 Qe7 18.Qb8+ Kf7 ± (1.20) Depth: 1 00:00:00 4.Rg3 Rf6 5.Rh3 Kf7 6.Qh7+ Kf8 7.exf5 Bxb3 8.axb3 gxf5 9.Rg3 Qe6 10.b4 Ke8 11.Rg8+ Rf8 12.Qh5+ Qf7 13.Rxf8+ Kxf8 14.Qh6+ Ke8 15.Qxc6+ Qd7 16.Qg6+ Qf7 17.Qd6 Qe7 18.Qb8+ Kf7 ± (1.20) Depth: 2 00:00:00 4.Rg3 Rf6 5.Rh3 Kf7 6.Qh7+ Kf8 7.exf5 Bxb3 8.axb3 gxf5 9.Rg3 Qe6 10.b4 Ke8 11.Rg8+ Rf8 12.Qh5+ Qf7 13.Rxf8+ Kxf8 14.Qh6+ Ke8 15.Qxc6+ Qd7 16.Qg6+ Qf7 17.Qd6 Qe7 18.Qb8+ Kf7 ± (1.20) Depth: 3 00:00:00 4.Rg3 Rf6 5.Rh3 Kf7 6.Qh7+ Kf8 7.exf5 Bxb3 8.axb3 gxf5 9.Rg3 Qe6 10.b4 Ke8 11.Rg8+ Rf8 12.Qh5+ Qf7 13.Rxf8+ Kxf8 14.Qh6+ Ke8 15.Qxc6+ Qd7 16.Qg6+ Qf7 17.Qd6 Qe7 18.Qb8+ Kf7 ± (1.20) Depth: 4 00:00:00 4.Rg3 Rf6 5.Rh3 Kf7 6.Qh7+ Kf8 7.exf5 Bxb3 8.axb3 gxf5 9.Rg3 Qe6 10.b4 Ke8 11.Rg8+ Rf8 12.Qh5+ Qf7 13.Rxf8+ Kxf8 14.Qh6+ Ke8 15.Qxc6+ Qd7 16.Qg6+ Qf7 17.Qd6 Qe7 18.Qb8+ Kf7 ± (1.20) Depth: 5 00:00:00 16kN 4.Rg3 Rf6 5.Rh3 Kf7 6.Qh7+ Kf8 7.exf5 Bxb3 8.axb3 gxf5 9.Rg3 Qe6 10.b4 Ke8 11.Rg8+ Rf8 12.Qh5+ Qf7 13.Rxf8+ Kxf8 14.Qh6+ Ke8 15.Qxc6+ Qd7 16.Qg6+ Qf7 17.Qd6 Qe7 18.Qb8+ Kf7 ± (1.20) Depth: 6 00:00:00 76kN 4.Rg3 Rf6 5.Rh3 Kf7 6.Qh7+ Kf8 7.exf5 Bxb3 8.axb3 gxf5 9.Rg3 Qe6 10.b4 Ke8 11.Rg8+ Rf8 12.Qh5+ Qf7 13.Rxf8+ Kxf8 14.Qh6+ Ke8 15.Qxc6+ Qd7 16.Qg6+ Qf7 17.Qd6 Qe7 18.Qb8+ Kf7 ± (1.20) Depth: 7 00:00:00 232kN 4.Rg3 Rf6 5.Rh3 Kf7 6.Qh7+ Kf8 7.exf5 Bxb3 8.axb3 gxf5 9.Rg3 Qe6 10.b4 Ke8 11.Rg8+ Rf8 12.Qh5+ Qf7 13.Rxf8+ Kxf8 14.Qh6+ Ke8 15.Qxc6+ Qd7 16.Qg6+ Qf7 17.Qd6 Qe7 18.Qb8+ Kf7 ± (1.20) Depth: 8 00:00:01 796kN 4.Rg3 Rf6 5.Rh3 Kf7 6.Qh7+ Kf8 7.exf5 Bxb3 8.axb3 gxf5 9.Rg3 Qe6 10.b4 Ke8 11.Rg8+ Rf8 12.Qh5+ Qf7 13.Rxf8+ Kxf8 14.Qh6+ Ke8 15.Qxc6+ Qd7 16.Qg6+ Qf7 17.Qd6 Qe7 18.Qb8+ Kf7 ± (1.20) Depth: 9 00:00:05 2723kN 4.Rg3 Rf6 5.Rh3 Kf7 6.Qh7+ Kf8 7.exf5 Bxb3 8.axb3 gxf5 9.Rg3 Qe6 10.b4 Ke8 11.Rg8+ Rf8 12.Qh5+ Qf7 13.Rxf8+ Kxf8 14.Qh6+ Ke8 15.Qxc6+ Qd7 16.Qg6+ Qf7 17.Qd6 Qe7 18.Qb8+ Kf7 ± (1.20) Depth: 10 00:00:18 8819kN (Blass, Tel-aviv 05.03.2002) > >I fed this to Fritz 7.0.0.6 and let it run all night on it. It found Nxg6 after >17 plies, but changed it's mind again, and on ply 19 it preferred Nf3 again. >Could you let Rebel run for an hour on the original to see the lines it >produces? > > Albert > > >>>and the question in this case is if Rebel can practically find the >>>winning move in the following position(I did not investigate to find the right >>>move): >>> >>>[D]4qrk1/8/pBn1b1pQ/1p2pp2/4P3/bBPR4/P4PPP/6K1 w - f6 0 4 >>> >>> >>>Here is yace main line before f7-f5 >>> >>>Analysis by Yace 0.99.56: >>> >>> >>>3...f5 4.Rh3 Kf7 5.exf5 Bxb3 6.fxg6+ Ke7 7.axb3 Rf6 8.Qh7+ Ke6 9.g7 Ne7 10.Rd3 >>>Qg6 11.Qh3+ Nf5 12.Bd8 >>> ² (0.26) Depth: 12 00:10:16 199936kN >> >> >>[d]4qrk1/8/pBn1b1pQ/1p2pp2/4P3/bBP4R/P4PPP/6K1 b - - 0 1 >> >>Following Rebel's analysis >> >>1. Rh3 Kf7 2. Qh7+ Kf6 3. Qh4+ Kg7 4. Bxe6 Qxe6 5. exf5 Qxf5 6. Qh6+ Kf7 7. Rf3 >>Qxf3 8. gxf3 1-0 >> >>or... >> >>1. Rh3 Kf7 2. Qh7+ Kf6 3. Qh4+ Kg7 4. Bxe6 Qxe6 5. exf5 Qxa2 6. Qh7+ Kf6 7. >>Qxg6+ Ke7 8. Rh7+ Rf7 9. Rxf7+ Qxf7 10. Qxc6 Qxf5 >> >>White is a healthy pawn up while the black king is draughty, Rebel's score still >>over 2 pawns, +2.39 to be exactly. >> >>Ed >> >> >> >> >> >>>(Blass, Tel-aviv 05.03.2002) >>> >>> >>>Uri
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