Author: Jeremiah Penery
Date: 21:12:25 08/29/99
Go up one level in this thread
On August 29, 1999 at 20:34:19, Howard Exner wrote: >On August 29, 1999 at 09:01:44, Mark Rawlings wrote: > >>On August 28, 1999 at 19:55:25, Howard Exner wrote: >> >>>On August 28, 1999 at 11:07:45, Mark Rawlings wrote: >>> >>>>On August 28, 1999 at 09:36:58, Howard Exner wrote: >>>> >>>>>On August 27, 1999 at 13:57:54, Mark Rawlings wrote: >>>>> >>>>>>I let Crafty with 3+2 tablebases chew on this one overnight after the moves c5 >>>>>>bxc5. After 25 ply, the eval was still +1.07 (Be1 Kc7 Ba5+ Kb8...) This one is >>>>>>really deep! >>>>>> >>>>>>Mark >>>>> >>>>>What line of play is Crafty producing? >>>> >>>>Here's the Crafty output: >>>> >>>> >>> >>>> 25 463:44 1.07 2. Be1 Kc7 3. Ba5+ Kb8 4. Ke3 Bd4+ >>>> 5. Ke2 Bf6 6. Kd3 Bb2 7. Kd2 Bf6 8.Ke3 <HT> >>> >>>How does Crafty play these lines as black? >>>I've always wanted to fiqure this position out and now with the >>>thre of us maybe we can do it. >>> >>>A.1. c5 bxc5 2. Be1 Kb8 3. Ba5 Kc8 4. b6 axb6 5. Bxb6 Kb8 6. Kc4 Bd4 7. Bd8 >>>Be3 8. Bxh4 Bxf4 9. Bf6 Bg3 10. h4 f4 11. Kd3 f3 12. Ke3 f2 13. Ke2 Ka7 >>>14. h5 Bf4 15. Bg7 Kxa6 16. Kxf2 Kb5 17. Kf3 Bg5 18. h6 >>> >>>B.1. c5 bxc5 2. Be1 Kb8 3. Ba5 Kc8 4. b6 axb6 5. Bxb6 Kb8 6. Kc4 Kc8 7. Kb5 >>>Kb8 8. Kc6 Be7 9. Kd7 Bf8 10. Ke6 >> >>After 3. Ba5 crafty has the following: >> >> 19-> 4:06 -1.22 3. ... Bb2 4. Bd8 Bc1 5. Bxh4 Bxf4 >> 6. Be1 Ka8 7. h4 Kb8 8. h5 Bh6 9. Bd2 >> f4 10. Ke4 f3 11. Be3 f2 12. Bxf2 Kc7 >> 13. Be3 >> 20 8:06 -1.18 3. ... Bb2 4. Bd8 Bc1 5. Bxh4 Bxf4 >> 6. Be1 Bh6 7. h4 Kc7 8. Ba5+ Kc8 9. >> b6 axb6 10. Bxb6 Kb8 11. h5 f4 12. >> Ke4 Kc8 13. Kf3 c4 14. a7 Kb7 >> 20-> 15:37 -1.18 3. ... Bb2 4. Bd8 Bc1 5. Bxh4 Bxf4 >> 6. Be1 Bh6 7. h4 Kc7 8. Ba5+ Kc8 9. >> b6 axb6 10. Bxb6 Kb8 11. h5 f4 12. >> Ke4 Kc8 13. Kf3 c4 14. a7 Kb7 >> 21 28:26 -1.34 3. ... Bb2 4. Bd8 Bc1 5. Bxh4 Bxf4 >> 6. Be7 Be5 7. h4 Kc7 8. h5 Bf4 9. Bf6 >> Kb6 10. Kc4 <HT> > >Instead of 6. Be7 input Be1. This looks harder to refute because it can >keep the black king out of b6 (If Kc7 then Ba5+). Also the h pawn moves >forward while it appears that black's c and f pawns are halted. For now I >see npo way out for black. > >> >>No sure thing yet for white. After 10. Ke6 in your line B.1. above, it looks >>like a win for white: >> >> 16-> 43.96 -3.28 8. ... Ka8 9. Kxf5 Bh6 10. Kg4 Bg7 >> 11. Kh5 c4 12. Kg6 Bf8 13. f5 c3 14. >> Bd4 c2 15. Be3 <HT> >> 17 1:13 -3.56 8. ... Ka8 9. Kxf5 Bh6 10. Kg4 c4 11. >> Be3 c3 12. Kh5 Bf8 13. Kg6 Be7 14. >> f5 Bd8 15. f6 Kb8 16. f7 <HT> >> 17-> 1:52 -3.56 8. ... Ka8 9. Kxf5 Bh6 10. Kg4 c4 11. >> Be3 c3 12. Kh5 Bf8 13. Kg6 Be7 14. >> f5 Bd8 15. f6 Kb8 16. f7 <HT> >> 18 2:04 -- 8. ... Ka8 >> 18 4:31 -6.45 8. ... Ka8 9. Kxf5 c4 10. Kg6 c3 11. >> f5 c2 12. Be3 Be7 13. f6 Bd8 14. Kg7 >> Kb8 15. f7 Be7 16. f8=Q+ Bxf8+ 17. >> Kxf8 <HT> >> >> >>I'll try to find the web site with the solutions to these. Maybe it has the >>winning line. (If not, it probably isn't a very good problem for a test suite!) > >It's definately a difficult problem for computers. The intent of the problem >could have been the initial position where most machines would just aimlessly >wander about behind the pawn wall. I human would quickly realize that the only >chance of a win is the break, c5. Whether that really wins remains but I >think that we will eventually resolve this one. >> >>Mark In the "Computer Chess Resource Center", there are solutions to all the LougetII problems. If you've not seen this solution already, here is what's given: 1.c5 (1....dxc5 2.d6 Kd7 3.Bxc5 Bd8 4.Bb4 Ke6 5.Kc4 Bf6 6.Bc5 Bd8 7.Bd4 Kxd6 8.Be5 Ke6 9.Bb8) OR (1....bxc5 2.Be1 Kb8 3.Kc4 Kc8 4.Ba5 Bd4 5.Bd8 Be3 6.Bg5 Kb8 7.Kd3 Bc1 8.Bxh4 Bxf4 9.Be1 Kc7 10.Ba5 Kb8 11.h4 Bc1 12.h5 Bg5 13.Ke2 c4 14.Bd2 Bf6 15.h6 1-0) There looks like there are a lot of alternative choices possible for both sides. The first variation doesn't isn't long enough, either, I think. I'm letting one of my modified Craftys search this, and at each greater ply depth it seems to be thinking on 1.c5 for a longer time. It's been the second move in the list since nearly the beginning. Ply 17 is being searched now...Perhaps it'll switch to c5 at some point, and I'll post the line given if it does. Jeremiah
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