Author: Dieter Buerssner
Date: 06:58:35 12/22/01
Go up one level in this thread
On December 22, 2001 at 07:12:00, Steffen Jakob wrote:
>I ran the JenoBan endgame test suite which I got from Lyapko Georges web server
>(http://www.geocities.com/lyapko/jenoban.htm). This is position #79 (the id tag
>is missing in the epd file from this server):
>
>r2k1B2/7R/p7/8/8/8/8/4K3 w - - bm Bc5; (JenoBan_TofE) #79 white_wins
>
>[D]r2k1B2/7R/p7/8/8/8/8/4K3 w - -
>
>Hossa switches between Bb4 and Bc5 but both with a drawish score. Crafty prefers
>Bd6 on my machine, also with a drawish score. Can someone please explain why Bc5
>is the best move here and how it wins? Or is this position broken?
I get this with my current version of Yace (k6-2 475):
4121339 39.141 0.67 11. 1. Bb4 Kc8 2. Ba5 Kb8 3. Bc3 Kc8 4. Be5 a5 5.
Rc7+ Kd8 6. Kd2 a4 7. Kc3
4551220 42.810 0.67 12t 1. Bb4 Kc8 2. Ba5 Kb8 3. Bc3 Kc8 4. Be5 a5 5.
Rc7+H Kd8H 6. Kd2H a4H 7. Kc3H {HT}
5869370 54.515 0.68 12t+ 1. Bc5 Rc8 2. Bb6+ Ke8 3. Ra7 a5 4. Ke2 a4 5.
Kd3 Rb8 6. Bc5 Rb4
6019791 56.026 0.96 12t 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5 4. Kd2 a4 5.
Kc3 a3 6. Kb3 a2H 7. Kxa2H {350}
7499853 1:08.1 0.96 12. 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5 4. Kd2 a4 5.
Kc3 a3 6. Kb3 a2 7. Kxa2 {350}
7515764 1:08.3 7.01 13++ 1. Bc5 Kc8 2. Ba7 a5 3. Kd2 a4 4. Kc3 Rb8 5.
Bxb8 a3
8468678 1:17.6 7.19 13t 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5 4. Kd2 a4 5.
Kc2 a3 6. Kb1 a2+ 7. Ka1 Kf8H 8. Rh8+H Ke7H
{270}
11513366 1:45.4 7.19 13. 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5 4. Kd2 a4 5.
Kc2 a3 6. Kb1 a2+ 7. Ka1 Kf8 8. Rh8+ Ke7 {270}
11778768 1:47.9 7.19 14t 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5 4. Kd2 a4 5.
Kc2 a3 6. Kb1 a2+ 7. Ka1 Kf8 8. Rh8+ Ke7 9.
Rxc8 {770}
18692520 2:49.7 7.19 14. 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5 4. Kd2 a4 5.
Kc2 a3 6. Kb1 a2+ 7. Ka1 Kf8 8. Rh8+ Ke7 9.
Rxc8 {770}
19109820 2:53.8 7.31 15t 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5 4. Kd2 a4 5.
Kc2 a3 6. Kb1 a2+ 7. Ka1 Kf8 8. Rh8+ Ke7 9.
Rxc8 Kd7 {770}
29910216 4:38.2 7.31 15. 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5 4. Kd2 a4 5.
Kc2 a3 6. Kb1 a2+ 7. Ka1 Kf8 8. Rh8+ Ke7 9.
Rxc8 Kd7 {770}
30238568 4:41.8 7.71 16++ 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5 4. Kd2 a4 5.
Kc2 Rd8 6. Bxd8 Kf8
30353254 4:42.8 8.71 16++ 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 Rb8 4. Bxb8 a5
31050713 4:50.1 10.00 16t 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5H 4. Kd2H a4H
5. Kc2H a3H 6. Kb1H a2+H 7. Ka1H Kf8H 8. Rh8+H
Ke7H 9. Rxc8H Kd7H 10. Rd8+H Kxc7H {420}
60896328 9:36.4 10.00 16. 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5 4. Kd2 a4 5.
Kc2 a3 6. Kb1 a2+ 7. Ka1 Kf8 8. Rh8+ Ke7 9.
Rxc8 Kd7 10. Rd8+ Kxc7 {420}
61241917 9:40.6 10.40 17++ 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5 4. Kd2 a4 5.
Kc2 a3 6. Kb1 a2+ 7. Ka1 Rb8 8. Bxb8 Kd8 9.
Kxa2 Kc8
61244887 9:40.6 11.40 17++ 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5 4. Kd2 a4 5.
Kc2 a3 6. Kb1 a2+ 7. Ka1 Rb8 8. Bxb8 Kd8 9.
Kxa2 Kc8
62427025 9:52.6 12.36 17t 1. Bc5 Rc8 2. Bb6+ Ke8 3. Bc7 a5 4. Kd2 a4 5.
Kc2 a3 6. Kb1 a2+ 7. Ka1 Kf8 8. Rh8+ Ke7 9.
Rxc8 Ke6 10. Kxa2 Kf5 {850}
And after 1. Bc5 Rc8 2. Bb6+ Ke8
3375354 33.208 12.62 17. 3. Bc7 a5 4. Kd2 a4 5. Kc2 a3 6. Kb1 a2+ 7. Ka1
Kf8 8. Rh8+ Ke7 9. Rxc8 Kd7 10. Ra8 Ke6 11.
Kxa2 Kd7 12. Ka3 {850}
3385384 33.375 Mat24 18++ 3. Bc7 a5 4. Kd2 a4 5. Kc2 a3 6. Kb1 a2+ 7. Ka1
Kf8 8. Rh8+ Ke7 9. Rxc8 Kd7 10. Ra8 Kxc7 {HT}
{420}
5631269 53.393 Mat21 18t 3. Bc7 a5 4. Kd2 a4 5. Kc2 a3 6. Kb1 a2+ 7. Ka1
Ra8 8. Rh8+ Kd7 9. Rxa8H Kxc7H {HT} {420}
7381560 1:08.1 Mat21 18. 3. Bc7 a5 4. Kd2 a4 5. Kc2 a3 6. Kb1 a2+ 7. Ka1
Ra8 8. Rh8+ Kd7 9. Rxa8 Kxc7 {HT} {420}
11496788 1:45.9 Mat21 19t 3. Bc7 a5 4. Kd2 a4 5. Kc2 a3 6. Kb1 a2+ 7. Ka1
Ra8 8. Rh8+ Kd7 9. Rxa8 Kxc7 {EGTB} 10. Ra6!
Kb7! 11. Rd6! Kc7 12. Rd3 Kc6 13. Kxa2! Kb5!
14. Rc3 Kb4! 15. Rc2 Kb5 16. Ka3 Ka6! 17. Rb2
Ka7 18. Rb3 Ka8 19. Ka4! Ka7 20. Ka5! Ka8 21.
Kb6! Kb8 22. Rc3! Ka8 23. Rc8#! {500}
14709542 2:14.9 Mat21 19. 3. Bc7 a5 4. Kd2 a4 5. Kc2 a3 6. Kb1 a2+ 7. Ka1
Ra8 8. Rh8+ Kd7 9. Rxa8 Kxc7 {EGTB} 10. Ra6!
Kb7! 11. Rd6! Kc7 12. Rd3 Kc6 13. Kxa2! Kb5!
14. Rc3 Kb4! 15. Rc2 Kb5 16. Ka3 Ka6! 17. Rb2
Ka7 18. Rb3 Ka8 19. Ka4! Ka7 20. Ka5! Ka8 21.
Kb6! Kb8 22. Rc3! Ka8 23. Rc8#! {500}
Going back, I get Mate in 23 for the root position.
I believe, details in null move implementation can make a big difference here.
Regards,
Dieter
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