Author: Howard Exner
Date: 17:34:19 08/29/99
Go up one level in this thread
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
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