Author: Dieter Buerssner
Date: 09:20:14 01/24/02
Go up one level in this thread
On January 23, 2002 at 23:24:24, Adam Stallard wrote:
>On January 23, 2002 at 13:40:19, Roy Eassa wrote:
>
>>On January 23, 2002 at 12:26:14, José Antônio Fabiano Mendes wrote:
>>
>>>Just one more position,a famous study by Emanuel Lasker,once the world champion.
>>> [D]2K5/2P2R2/k7/8/8/8/2r2p2/8 w
>>> 1.Kb8 Rb2+ 2.Ka8! Rc2 3.Rf6+ Ka5 4.Kb7 Rb2+ 5.Ka7 Rc2 6.Rf5+ Ka4
>>> 7.Kb6 Rb2+ 8.Ka6 Rc2 9.Rf4+ Ka3 10.Kb6 Rb2+ 11.Ka5! Rc2 12.Rxf2!! +-
>>
>>
>>A nice puzzle. Has anybody had this solved instantly (or nearly instantly) by
>>their computer using TBs?
In this position, TBs do not help too much, even when it is very close to TBs.
Yace gets the line without TBs and a little patience.
>The line given isn't right you need 12. Rf3+ Ka2 13. Rxf2 pinning the rook.
Yes.
Or:
352175001 49:50.5 Mat39 18t 1. Kb8 Rb2+ 2. Ka8 Rc2 3. Rf6+ Ka5 4. Kb7 Rb2+
5. Ka7 Rc2 6. Rf5+ Ka4 7. Kb7 Rb2+ 8. Ka6 Rc2
9. Rf4+ Ka3 10. Kb6 Rb2+ 11. Ka5 Kb3 12. Rxf2
{EGTB} 12...Rxf2! 13. c8=Q!! Rc2! 14. Qf5! Kc3!
15. Kb5! Re2! 16. Qf3+ Kd2! 17. Kc4! Ke1! 18.
Qg3+ Kf1! 19. Qh3+! Ke1! 20. Qh4+! Kf1! 21.
Kd3! Rg2! 22. Qh3! Kg1 23. Qe3+! Kh1 24. Qe4
Kh2! 25. Ke3! Kh3! 26. Qc6! Rg5 27. Kf4! Rg4+!
28. Kf3! Rg3+! 29. Kf2! Rg5! 30. Qe4! Rg7 31.
Qe6+! Kh4! 32. Qh6+! Kg4 33. Qxg7+! Kf5! 34.
Qe7! Kg6! 35. Kg2 Kh6 36. Kf3! Kg6! 37. Kf4
Kh6! 38. Kf5! Kh5 39. Qh7# {1001}
Decisive advantage is found much earlier. To get the mate score directly from
the root position, I told Yace to use TBs more aggressively than normal.
After 11...Rc2:
83830 4.539 Mat28 9u. 12. Rf3+ Kb2 13. Rxf2 {EGTB} 13...Rxf2! 14.
c8=Q!! Rc2! 15. Qh8+ Kc1! 16. Qd4! Rd2! 17.
Qf4! Kd1! 18. Qf1+! Kc2 19. Kb5 Rd4 20. Kc5!
Rd8 21. Qf5+! Kb3! 22. Qe6+! Kc2! 23. Kc4! Rd2!
24. Qe4+ Kb2 25. Kb4! Rc2! 26. Qe1! Rc8! 27.
Qe5+! Kc1! 28. Kb3! Kd1 29. Qf5 Rd8 30. Qh5+
Ke1 31. Qh4+! Kf1 32. Qxd8! Kf2 33. Qg8 Kf3 34.
Qg5! Kf2 35. Qg4 Kf1 36. Kc3 Kf2! 37. Kd3 Kf1!
38. Ke3! Ke1 39. Qg1# {1001}
Moves with ! are the only optimal moves (longest mate for black, shortest mate
for white, but alternatives win as well), moves with !! the only winning moves.
So a mate with the same length. Without TBs, the essential line is found at
about the same speed, which is not too surprising here, because the win of the
pawn wins the game. The pawn win will not rise the score so much as a lookup in
the TBs, but will probably be enough to win the game for chess engines. In other
cases the KRPKR TB can be much more useful, especially when the chess engine has
not any (sophisticated) knowledge of this endgame.
Without TBs, all on K6-2 475.
[Kb8 choosen from the beginning, because of positional reason, one could say
because of luck...]
10234253 1:06.2 0.18 14. 1. Kb8 Rb2+ 2. Ka8 Rc2 3. Rf6+ Ka5 4. Kb7 Rb2+
5. Ka7 Rc2 6. Rf5+ Ka4 7. Rf4+ Ka5 8. Kb7 Rb2+
9. Kc6 Rc2+ 10. Kd7 Rd2+ 11. Ke6 Rc2 12. Kd6 {0}
11490055 1:13.2 0.58 15++ 1. Kb8 Rb2+ 2. Ka8 Rc2 3. Rf6+ Ka5 4. Kb7 Rb2+
5. Ka7 Rc2 6. Rf5+ Ka4 7. Kb7 Rb2+ 8. Ka6 Rc2
9. Rf4+ Rc4 10. c8=Q Rxf4 {421}
11792148 1:14.9 1.58 15++ 1. Kb8 Rb2+ 2. Ka8 Rc2 3. Rf6+ Ka5 4. Kb7 Rb2+
5. Ka7 Rc2 6. Rf5+ Ka4 7. Kb7 Rb2+ 8. Ka6 Rc2
9. Rf4+ Rc4 10. c8=Q Rxf4 {421}
12395595 1:18.7 1.65 15t 1. Kb8 Rb2+ 2. Ka8 Rc2 3. Rf6+ Ka5 4. Kb7 Rb2+
5. Ka7 Rc2 6. Rf5+ Ka4 7. Kb7 Rb2+ 8. Ka6 Rc2
9. Rf4+ Kb3 10. Kb6 f1=Q 11. Rxf1 {80}
21174923 2:20.6 1.65 15. 1. Kb8 Rb2+ 2. Ka8 Rc2 3. Rf6+ Ka5 4. Kb7 Rb2+
5. Ka7 Rc2 6. Rf5+ Ka4 7. Kb7 Rb2+ 8. Ka6 Rc2
9. Rf4+ Kb3 10. Kb6 f1=Q 11. Rxf1 {80}
24751464 2:42.4 1.64 16t 1. Kb8 Rb2+ 2. Ka8 Rc2 3. Rf6+ Ka5 4. Kb7 Rb2+
5. Ka7 Rc2 6. Rf5+ Ka4 7. Kb7 Rb2+ 8. Ka6 Rc2
9. Rf4+ Ka3 10. Kb6 Rc3 11. Rxf2 Kb4 {HT} {80}
51058535 5:40.7 1.64 16. 1. Kb8 Rb2+ 2. Ka8 Rc2 3. Rf6+ Ka5 4. Kb7 Rb2+
5. Ka7 Rc2 6. Rf5+ Ka4 7. Kb7 Rb2+ 8. Ka6 Rc2
9. Rf4+ Ka3 10. Kb6 Rc3 11. Rxf2 Kb4 {HT} {80}
58363302 6:26.7 1.67 17t 1. Kb8 Rb2+ 2. Ka8 Rc2 3. Rf6+ Ka5 4. Kb7 Rb2+
5. Ka7 Rc2 6. Rf5+ Ka4 7. Kb7 Rb2+ 8. Ka6 Rc2
9. Rf4+ Ka3 10. Kb6 Rb2+ 11. Ka5 f1=Q 12. Rxf1
Rc2 {80}
107794490 12:11.1 1.67 17. 1. Kb8 Rb2+ 2. Ka8 Rc2 3. Rf6+ Ka5 4. Kb7 Rb2+
5. Ka7 Rc2 6. Rf5+ Ka4 7. Kb7 Rb2+ 8. Ka6 Rc2
9. Rf4+ Ka3 10. Kb6 Rb2+ 11. Ka5 f1=Q 12. Rxf1
Rc2 {80}
124467201 13:54.6 1.70 18t 1. Kb8 Rb2+ 2. Ka8 Rc2 3. Rf6+ Ka5 4. Kb7 Rb2+
5. Ka7 Rc2 6. Rf5+ Ka4 7. Kb7 Rb2+ 8. Ka6 Rc2
9. Rf4+ Ka3 10. Kb6 Rb2+ 11. Ka5 f1=Q 12. Rxf1
Rc2 13. Kb6 {80}
Here until 11...Ka5 the same line as given by JAFM.
Regards,
Dieter
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.