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Subject: Re: Black to move and draw (should be easier for programs?)

Author: Roy Eassa

Date: 12:49:28 04/01/02

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On April 01, 2002 at 14:36:35, Dieter Buerssner wrote:

>On April 01, 2002 at 13:40:13, Roy Eassa wrote:
>
>>
>>[d] 8/8/5kpp/3K1p2/5P2/7P/6P1/8 b - - 0 1
>>Black to move and draw.
>>
>>I would think this would be trivially easy for today's programs running on fast
>>PCs, but (maybe) it isn't.  There are only two first moves for Black that draw;
>>everything else loses:
>>
>>1...g5!
>>
>>   [also drawing is 1...Kf7 2.Kd6
>>      (2.h4 g5 3.h5 gxf4 4.Ke5 Ke7 5.Kxf5 Kf7 6.Kxf4 Kf6 7.g3 Ke6 =)
>>    2...Kf6 3.h4 g5 4.g3 Kg6 5.hxg5
>>       (5.Ke6 g4=)
>>    5...hxg5 6.Ke6 gxf4 7.gxf4 Kg7 8.Kxf5 Kf7 =]
>>
>>   [1...h5? 2.h4 +-
>>      (2.g3 also wins)]
>>
>>   [1...Ke7? 2.Ke5+-]
>>
>>2.g3 g4 3.h4
>>
>>   [3.hxg4 fxg4 and Black pushes the pawn to h4 for a simple draw.]
>>
>>3...Kg6 4.Ke5 Kh5 =
>
>Yace needs a bit of time, to find g5.
>
>   1853091  36.172  -0.14 16.  1...h5 2. h4 Ke7 3. Ke5 Kf7 4. Kd6 Kf6 5. Kd7
>                               Kf7 6. g3 Kf6 7. Kd6 Kf7 8. Kc5 Ke7 9. g4 hxg4
>                               10. Kc6 g3 11. Kb5 g2 12. h5
>   2262485  42.866  -0.54 17-- 1...h5 2. g3 Ke7 3. Ke5 Kf7 4. Kd6 Kf6 5. Kd7
>                               h4 6. gxh4 Kg7 7. Kd6 Kf7 8. Kc5 Kf6 9. Kd5 Kf7
>                               10. Ke5 Ke8H 11. h5H g5H 12. fxg5H f4H {HT}
>   2543136  48.921  -0.55 17t  1...h5 2. g3 Ke7 3. Ke5 Kf7H 4. Kd6H Kf6H 5.
>                               Kd7H Kf7H 6. Kd8H Kf6H 7. Ke8H g5H 8. Kf8H h4H
>                               9. gxh4H gxh4H 10. Kg8H Kg6H 11. Kh8H Kh5H 12.
>                               Kg8H Kh6H 13. Kf7H Kh7H {0}
>   3140092  1:09.2  -0.54 17t+ 1...g5 2. g3 g4 3. Kd6 Kg6 4. Ke5 Kh5 5. Kxf5
>                               gxh3 6. g4+ Kh4 7. Ke5 Kg3 8. f5 Kg2 9. f6 h2
>                               10. f7
>   3435587  1:14.8  -0.24 17t  1...g5 2. g3 g4 3. h4 Kg6 4. Ke5 Kh5 5. Ke6H
>                               Kg6H 6. Ke7H Kh5H 7. Kd6H Kg6H 8. Kd5H Kh5H 9.
>                               Ke5H Kg6H 10. Kd4H Kh5H 11. Kc5H Kg6H 12. Kd5H
>                               Kh5H 13. Ke5H Kg6H 14. Kd4H Kh5H 15. Kc5H Kg6H
>                               16. Kd5HR {0}
>   3797157  1:26.0  -0.24 17.  1...g5 2. g3 g4 3. h4 Kg6 4. Ke5 Kh5 5. Ke6 Kg6
>                               6. Ke7 Kh5 7. Kd6 Kg6 8. Kd5 Kh5 9. Ke5 Kg6 10.
>                               Kd4 Kh5 11. Kc5 Kg6 12. Kd5 Kh5 13. Ke5 Kg6 14.
>                               Kd4 Kh5 15. Kc5 Kg6 16. Kd5 {0}
>   4408911  1:38.4  -0.24 18t  1...g5 2. g3 g4 3. h4 Kg6 4. Ke5 Kh5 5. Ke6 Kg6
>                               6. Ke7 Kh5 7. Kd6 Kg6 8. Kd5 Kh5H 9. Ke6H Kg6H
>                               10. Ke7H Kh5H 11. Kd6H Kg6H 12. Kd5H Kh5H 13.
>
>And essentially the same for some time. The fail low for h5 does not look
>impressive, but with the next depth, it would be much more negative. For Ke7,
>the behaviour is similar. It first looks reasonable, but soon fails low big
>time. If I disallow g5 (my "poor man's n-best mode) I get a similar score with
>Kf7 as the best move. All on K6-2 475.
>
>Regards,
>Dieter



Is there ANY chess program (running on a fast PC) that can see, fairly quickly,
that 1...g5 draws AND that 1...h5 loses?

(No offense, but showing -0.54 for the losing move and -0.24 for the drawing
move is not as decisive as one might imagine.)



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