Author: Miguel A. Ballicora
Date: 10:58:27 07/08/02
Go up one level in this thread
On July 07, 2002 at 15:39:04, Steve Maughan wrote: >Mike, > >Is WAC 230 correct? If I remember corretly there was a discussion here a few >months back that said that Rb4 was not such a forced win e.g. > >http://www.it.ro/ccc_search/ccc.php?art_id=163138 > >Regards, > >Steve I still think that WAC230 is a win for black. I did not have time to do an analysis and _prove_ it but my intuition tells me so. I reproduce the post and answer later. Subject : WAC 230 ---------------------------------------------------------------------------- Posted by : Bruce Moreland on April 13, 2001 at 04:14:13 This is from a post by Alex Szabo. #230 [Rb4 does not win. The main line is, 1... Rb4!? 2. cxb4 a4 3. b5+ Kxb5 4. Ba3 c3 5. Re2! Kc4 6. f4 Kxd4 7. f5 exf5 8. e6 Kd3 9. e7 Bd7 10. Kf3 d4 11. Rh2 Kc4 12. Rh8 b2 13. Rb8 d3 14. Bxb2 cxb2 15. Rxb2 a3 16. Rb7 Be8 17. Ra7 Kb3 18. Ke3 a2 19. Kxd3 Kb2 20. Rb7+ Kc1 21. Ra7 =] Ra7, Rb6, Rb5, Rd7, Rf7, Rg7, Rh7, Bd7, Kd7, Kb6, Kb5, a4, and Rc7 are just as good as the book solution Rb4 -- they all hold the game. [D]2b5/1r6/2kBp1p1/p2pP1P1/2pP4/1pP3K1/1R3P2/8 b - - 0 1 I think this is worth thinking about. After 1. ... Rb4 2. cxb4 a5 3. b5+ Kxb5 4. Ba3 c3 5. Re2 Kc4 6. f4, we get this: [D]2b5/8/4p1p1/3pP1P1/p1kP1P2/Bpp3K1/4R3/8 b - - 0 1 6. ... Bd7 is a possibility, but still seems like a draw. There is some fascinating stuff going on in the main line. WAC attributes this to Nimzovich, but doesn't give a game reference. I doubt that the position is solvable by a computer, and if anyone "finds" this, they've got some lucky eval terms. bruce ------------------------------------------------------------------------------- The position is from the book "my system", so it is well known from there, not from WAC. IIRC when I looked to this analysis, 6... Bd7 wins. I am "remembering" blindfold, so beware. For instance, you can answer 7.f5 with Be8. There is no need to give counterchances to white on the king side. Why doing it? White is lost in the queen side. One thing is certain, Szabo's move 5. Re2! I is much stronger than the "classical" PV (that came from the Nimzovich game). Regards, Miguel > > >>Through my years of testing WAC positions, WAC 230 has been the toughest with my >>modified crafty's - my crafty's have never solved it (in a reasonable time)... >>my latest version of modified crafty (so far unrelease) solves is < 1 minute on >>a Dual P4 1.7Ghz >> >>[D] 2b5/1r6/2kBp1p1/p2pP1P1/2pP4/1pP3K1/1R3P2/8 b - - >> >> >>Black(1): go >>end-game phase >> clearing hash tables >> time surplus 0.00 time limit 10:00 (10:00) >> nss depth time score variation (1) >> 10 0.46 1.64 1. ... Rh7 2. Kf4 Rh3 3. f3 Rh1 4. >> Ke3 Re1+ 5. Kd2 Rg1 6. Be7 Rg2+ 7. >> Kc1 >> 10-> 0.46 1.64 1. ... Rh7 2. Kf4 Rh3 3. f3 Rh1 4. >> Ke3 Re1+ 5. Kd2 Rg1 6. Be7 Rg2+ 7. >> Kc1 >> 11 1.04 1.69 1. ... Rh7 2. Rb1 Bd7 3. f3 Rh5 4. >> Be7 Be8 5. Rb2 Kd7 6. Bf6 a4 >> 11-> 1.04 1.69 1. ... Rh7 2. Rb1 Bd7 3. f3 Rh5 4. >> Be7 Be8 5. Rb2 Kd7 6. Bf6 a4 >> 12 1.63 1.66 1. ... Rh7 2. Rb1 a4 3. Ba3 Bb7 4. >> Rb2 Rh1 5. Bf8 Rc1 6. Bb4 Rg1+ 7. Kf4 >> Rg2 <HT> >> 12-> 1.63 1.66 1. ... Rh7 2. Rb1 a4 3. Ba3 Bb7 4. >> Rb2 Rh1 5. Bf8 Rc1 6. Bb4 Rg1+ 7. Kf4 >> Rg2 <HT> >> 13 2.99 1.65 1. ... Rh7 2. Rb1 Bb7 3. f3 Rf7 4. >> Ra1 Ba6 5. Rb1 a4 6. Rb2 Rf5 7. Kg4 >> Kd7 <HT> >> 13-> 3.24 1.65 1. ... Rh7 2. Rb1 Bb7 3. f3 Rf7 4. >> Ra1 Ba6 5. Rb1 a4 6. Rb2 Rf5 7. Kg4 >> Kd7 <HT> >> 14 4.04 1.67 1. ... Rh7 2. Rb1 Bb7 3. f3 a4 4. Ba3 >> Kd7 5. Rb2 Rh1 6. Rh2 Ra1 7. Bb2 Rf1 >> 8. Kf4 >> 14-> 4.08 1.67 1. ... Rh7 2. Rb1 Bb7 3. f3 a4 4. Ba3 >> Kd7 5. Rb2 Rh1 6. Rh2 Ra1 7. Bb2 Rf1 >> 8. Kf4 >> 15 9.99 1.68 1. ... Rh7 2. Rb1 Rh5 3. Kg4 a4 4. >> Ba3 Kd7 5. Kf4 Bb7 6. f3 Ba6 7. Rb2 >> <HT> >> 15-> 11.16 1.68 1. ... Rh7 2. Rb1 Rh5 3. Kg4 a4 4. >> Ba3 Kd7 5. Kf4 Bb7 6. f3 Ba6 7. Rb2 >> <HT> >> 16 20.80 1.77 1. ... Rh7 2. Rb1 Bb7 3. Ra1 Ba6 4. >> Ba3 a4 5. Bb2 Bb5 6. f3 Kd7 7. Rb1 >> Rh5 8. Kf4 <HT> >> 16 40.27 2.14 1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. >> Ba3 c3 5. Rb1 Kc4 6. Rc1 Kxd4 7. f4 >> Bd7 8. Bb4 c2 9. Ba3 Kc3 10. f5 >> (2) 16-> 40.27 2.14 1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. >> Ba3 c3 5. Rb1 Kc4 6. Rc1 Kxd4 7. f4 >> Bd7 8. Bb4 c2 9. Ba3 Kc3 10. f5 >> 17 1:02 ++ 1. ... Rb4!! >> 17 1:22 2.58 1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. >> Ba3 c3 5. Rb1 Kc4 6. Rc1 Kxd4 7. f4 >> Kd3 8. Rd1+ Kc2 9. Rh1 b2 10. f5 d4 >> 11. fxe6 >> 17-> 1:23 2.58 1. ... Rb4 2. cxb4 a4 3. b5+ Kxb5 4. >> Ba3 c3 5. Rb1 Kc4 6. Rc1 Kxd4 7. f4 >> Kd3 8. Rd1+ Kc2 9. Rh1 b2 10. f5 d4 >> 11. fxe6 >> time=1:23 cpu=197% mat=1 n=106708755 fh=89% nps=1285028 >> ext-> checks=3362292 recaps=55887 pawns=957944 1rep=74596 >>thrt:1669 >> predicted=0 nodes=106708755 evals=19420883 >> endgame tablebase-> probes done=0 successful=0 >> SMP-> split=1620 stop=242 data=10/64 cpu=2:43 elap=1:23
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