Author: Dieter Buerssner
Date: 16:48:48 04/07/04
Go up one level in this thread
This ideas works surprisingly well in some of my favorite chess positions. I
made it even simpler: just extend 1/2 ply, as long as no pieces are on the board
(2 lines of code). Of course, this will give a lower general search depth. A
difficult study by Grigoriev (see also
http://chessprogramming.org/cccsearch/ccc.php?art_id=190804)
[D] k7/8/pp6/2p4K/8/PPP5/8/8 w - -
12633748 13.278 0.24 16. 1.c4 Kb7 2.a4 Kc6 3.Kg5 Kc7 4.Kf6 Kd7 5.a5 Kd6
6.Kf5 Kc7 7.Ke5 Kd7 8.Kd5 Kc7 9.Ke6 Kc6 10.Kf7
Kd7 11.Kf6 Kd6 12.Kf5 Kc7 13.Ke5 Kd7 14.Kd5 Kc7
15.Ke6 Kc6 16.Kf7 Kd7 17.Kf6 {0}
13847685 15.116 0.64 17++ 1.c4 Kb7 2.a4 Kc6 3.Kg5 Kd7 4.Kf6 b5 5.Ke5 Kc7
6.Kd5 Kb6 7.a5+ Kxa5 8.Kxc5 b4 9.Kd6 Kb6 10.c5+
Ka7 11.c6 a5 12.c7 a4 13.c8=Q a3
13919076 15.188 1.64 17++ 1.c4 Kb7 2.a4 Kc6 3.Kg5 Kd7 4.Kf6 b5 5.Ke5 Ke8
6.cxb5 Kf8 7.b6 Kg7 8.b7 c4 9.b8=Q c3
14099703 15.367 6.64 17++ 1.c4 Kb7 2.a4 Kc6 3.Kg5 Kd7 4.Kf6 a5 5.Kf7 Kc6
6.Ke8 Kc7 7.Ke7 Kb7 8.Kd8 Ka8 9.Kc7 b5 10.cxb5
Ka7 11.b6+ Ka6 12.b7 c4 13.b8=Q c3
17913107 19.866 6.66 17t 1.c4 Kb7 2.a4 Kc6 3.Kg5 Kd7 4.Kf6 Kc7H 5.Ke6H
Kc6H 6.a5H Kc7H 7.Kd5H Kb7H 8.Kd6H bxa5H
9.Kxc5H Kc7H 10.Kd5H Kd7H 11.c5H Ke8H 12.Kc6H
Ke7H 13.Kb6H Kf6H 14.Kb7H Kf7H 15.c6H Ke6H
16.c7H a4H 17.c8=Q+H Ke5H {HT}
19497987 21.987 6.66 17. 1.c4 Kb7 2.a4 Kc6 3.Kg5 Kd7 4.Kf6 Kc7 5.Ke6 Kc6
6.a5 Kc7 7.Kd5 Kb7 8.Kd6 bxa5 9.Kxc5 Kc7 10.Kd5
Kd7 11.c5 Ke8 12.Kc6 Ke7 13.Kb6 Kf6 14.Kb7 Kf7
15.c6 Ke6 16.c7 a4 17.c8=Q+ Ke5
22818655 26.283 6.26 18-- 1.c4 Kb7 2.a4 Kc6 3.Kg5 Kc7 4.Kf6 Kd7 5.a5 Kd6
6.b4 cxb4 7.axb6 b3 8.Kf5 b2 9.b7 b1=Q+ 10.Kf4
29248048 34.290 6.24 18t 1.c4 Kb7 2.a4 Kc6 3.Kg5 Kc7 4.Kg6H a5H 5.Kg7H
Kc6H 6.Kf8H b5H 7.cxb5+H Kd6H 8.b6H Kc6H 9.Ke7H
Kd5H 10.b4H c4H 11.b7H c3H 12.b8=QH Kd4H {HT}
31462915 36.882 6.24 18. 1.c4 Kb7 2.a4 Kc6 3.Kg5 Kc7 4.Kg6 a5 5.Kg7 Kc6
6.Kf8 b5 7.cxb5+ Kd6 8.b6 Kc6 9.Ke7 Kd5 10.b4
c4 11.b7 c3 12.b8=Q Kd4
31738662 37.218 6.64 19++ 1.c4 Kb7 2.a4 Kc6 3.Kg5 b5 4.a5 Kd6 5.Kf5 Kd7
6.Ke5 Kd8 7.Kd5 Ke7 8.cxb5 Kf6 9.b4 cxb4 10.b6
b3 11.b7 b2 12.b8=Q b1=N
36154165 43.146 6.64 19t 1.c4 Kb7 2.a4 Kb8H 3.Kg5H Kc8H 4.Kf5H Kd8H
5.a5H Kc7H 6.Kf6H Kd6H 7.Kg5H Ke6H 8.b4H cxb4H
9.axb6H Kd6H 10.c5+H Kd7H 11.Kf4H b3H 12.b7H
Kc7H 13.Ke4H b2H 14.Kf3H b1=QH 15.b8=RH {HT}
38726838 46.246 6.64 19. 1.c4 Kb7 2.a4 Kb8 3.Kg5 Kc8 4.Kf5 Kd8 5.a5 Kc7
6.Kf6 Kd6 7.Kg5 Ke6 8.b4 cxb4 9.axb6 Kd6 10.c5+
Kd7 11.Kf4 b3 12.b7 Kc7 13.Ke4 b2 14.Kf3 b1=Q
15.b8=R
46308310 53.550 6.24 20-- 1.c4 Kb7 2.a4 Kb8 3.Kg5 Kc8 4.Kf5 Kd8 5.a5 Kc7
6.Kf6 Kd6 7.Kg5 Ke6 8.b4 cxb4 9.axb6 Kd6 10.c5+
Kd7 11.Kg6 b3 12.Kf6 b2 13.b7 b1=Q 14.b8=Q Qxb8
15.Kg5
66581558 1:14.5 6.22 20t 1.c4 Kb7 2.a4 Kb8 3.Kg5 Kc8 4.a5H Kd7H 5.Kf5H
Kc7H 6.Ke5H Kd7H 7.Kd5H Kd8H 8.axb6H Kc8H
9.Kxc5H Kb7H 10.b4H a5H 11.bxa5H Ka6H 12.b7H
Ka7H 13.b8=Q+H Ka6H {HT}
70198330 1:18.8 6.22 20. 1.c4 Kb7 2.a4 Kb8 3.Kg5 Kc8 4.a5 Kd7 5.Kf5 Kc7
6.Ke5 Kd7 7.Kd5 Kd8 8.axb6 Kc8 9.Kxc5 Kb7 10.b4
a5 11.bxa5 Ka6 12.b7 Ka7 13.b8=Q+ Ka6
81670670 1:32.4 6.60 21t 1.c4 Kb7 2.a4 a5 3.Kh6 Kc7 4.Kg7 Kc6 5.Kf8H b5H
6.cxb5+H Kd5H 7.b6H Ke4H 8.b7H c4H 9.b8=QH c3H
{HT}
86447080 1:39.3 6.60 21. 1.c4 Kb7 2.a4 a5 3.Kh6 Kc7 4.Kg7 Kc6 5.Kf8 b5
6.cxb5+ Kd5 7.b6 Ke4 8.b7 c4 9.b8=Q c3
87153087 1:40.7 7.00 22++ 1.c4 Kb7 2.a4 a5 3.Kh6 Kc7 4.Kg7 Kc6 5.Kf8 b5
6.cxb5+ Kc7 7.Ke8 Kc8 8.Ke7 c4 9.bxc4 Kc7 10.c5
Kc8 11.c6 Kb8 12.Kd6 Ka7 13.c7 Ka8 14.c8=Q+ Ka7
87826257 1:41.4 8.00 22++ 1.c4 Kb7 2.a4 a5 3.Kh6 Kc7 4.Kg7 Kc6 5.Kf8 b5
6.cxb5+ Kc7 7.Ke8 Kc8 8.Ke7 c4 9.bxc4 Kc7 10.c5
Kc8 11.c6 Kb8 12.Kd6 Ka7 13.c7 Ka8 14.c8=Q+ Ka7
204463928 3:46.4 12.90 22t 1.c4 Kb7 2.a4 Kc7 3.Kg6 Kc6 4.Kf5 Kc7 5.a5 Kc8
6.Ke6 Kc7 7.Kd5 Kb7 8.Kd6 bxa5 9.Kxc5 Kc7
10.Kd5 Kd7 11.c5 Kc7 12.c6 Kd8 13.Kc4 Kc8
14.Kd4 Kd8 15.Kd5 Ke7 16.Kc5 Ke6 17.Kb6H a4H
18.bxa4H Kd5H 19.c7H Kd6H 20.c8=QH Kd5H 21.a5H
Ke4H {HT}
237173789 4:21.2 12.90 22. 1.c4 Kb7 2.a4 Kc7 3.Kg6 Kc6 4.Kf5 Kc7 5.a5 Kc8
6.Ke6 Kc7 7.Kd5 Kb7 8.Kd6 bxa5 9.Kxc5 Kc7
10.Kd5 Kd7 11.c5 Kc7 12.c6 Kd8 13.Kc4 Kc8
14.Kd4 Kd8 15.Kd5 Ke7 16.Kc5 Ke6 17.Kb6 a4
18.bxa4 Kd5 19.c7 Kd6 20.c8=Q Kd5 21.a5 Ke4
And a study by Averbach (I first saw it posted here by Peter McKenzie, but
cannot find fast the original post now)
[D] 2k2K2/8/pp6/2p5/2P5/PP6/8/8 w - -
8222907 11.127 0.19 17t 1.Ke8 Kc7 2.a4 b5 3.Ke7 Kb6 4.Kd6 b4 5.Kd5 Ka5
6.Ke4 Kb6 7.Kf4 Ka5 8.Ke5 Kb6 9.Ke6H Ka5H
10.Kd5H Kb6H 11.Kd6H Ka5H 12.Ke7H Kb6H 13.Kf7H
Ka5H 14.Kg7H Kb6H 15.Kg6H Ka5H 16.Kg5H Kb6H
17.Kg6H Ka5H 18.Kg5H Kb6H 19.Kg6HR {0}
8408250 11.450 0.20 17t+ 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kc7
6.Ke6 Kc6 7.Ke7 Kc7 8.Ke8 bxa5 9.Ke7 Kc8
10.Kd6H Kb8H 11.Kxc5H Kb7H 12.Kd4H Kc6H 13.c5H
Kd7H 14.Kd5H Ke7H 15.c6H Kf7H 16.c7H a4H
17.c8=QH Kf6H {HT}
9174737 12.985 0.21 17t 1.a4 Kd7 2.a5 bxa5 3.Kf7 Kc7 4.Ke7H Kb6H 5.Kd6H
Ka7H 6.Kxc5H Kb7H 7.Kd6H Kb6H 8.c5+H Kb5H 9.c6H
Kb4H 10.c7H a4H 11.c8=QH a3H {HT}
9960367 14.284 0.21 17. 1.a4 Kd7 2.a5 bxa5 3.Kf7 Kc7 4.Ke7 Kb6 5.Kd6
Ka7 6.Kxc5 Kb7 7.Kd6 Kb6 8.c5+ Kb5 9.c6 Kb4
10.c7 a4 11.c8=Q a3
11302662 16.114 0.58 18t 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kc7
6.Ke6H bxa5H 7.Kd5H Kb7H 8.Kxc5H Kc7H 9.Kd5H
Kd7H 10.c5H Kc7H 11.c6H Kb6H 12.Kd6H Ka7H
13.c7H Kb7H 14.b4H a4H 15.b5H a5H 16.b6H Kc8H
17.Kc5H Kd7H 18.Kd4H a3H 19.Kc3H Kd6H 20.c8=QH
a2H 21.b7H a1=Q+H 22.Kd3H {0}
12563904 18.218 0.58 18. 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kc7
6.Ke6 bxa5 7.Kd5 Kb7 8.Kxc5 Kc7 9.Kd5 Kd7 10.c5
Kc7 11.c6 Kb6 12.Kd6 Ka7 13.c7 Kb7 14.b4 a4
15.b5 a5 16.b6 Kc8 17.Kc5 Kd7 18.Kd4 a3 19.Kc3
Kd6 20.c8=Q a2 21.b7 a1=Q+ 22.Kd3 {0}
12737474 18.665 0.98 19++ 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kc7
6.Ke6 bxa5 7.Kd5 Kb7 8.Kxc5 Kc7 9.Kd5 Kd7 10.c5
Kc8 11.Kd6 Kb8 12.Kc6 Kc8H 13.Kb6H Kd7H 14.c6+H
Kd6H 15.c7H Ke5H 16.c8=QH a4H {HT}
12962639 18.922 1.98 19++ 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kc7
6.Ke6 Kc6 7.Ke7 Kc7 8.Ke8 Kd6 9.axb6 Kc6 10.Kd8
Kd6 11.Kc8 a5 12.Kb8 Kc6 13.b7 Kd6 14.b4 a4
15.Ka8 Ke6 16.b8=Q Kd7
13335035 19.467 6.98 19++ 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kd7
6.Ke5 Kc6 7.Ke6 b5 8.Ke5 Kd7 9.Kd5 b4 10.Kxc5
Ke6 11.Kxb4 Kd6 12.Ka4 Kc5 13.Ka3 Kd4 14.Kb2
Kc5 15.Kc3 Kd6 16.b4 Ke5 17.b5 Kf6 18.b6 Kg6
19.c5 Kf5H 20.c6H Ke6H 21.b7H Kd6H 22.b8=Q+H
Kxc6H {HT}
15149102 22.409 8.00 19t 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kd7
6.Ke5 Kc6 7.Ke6 Kc7 8.Kd5 Kb7 9.Kd6 bxa5
10.Kxc5 Kc7 11.Kd5 Kd7 12.c5 Kc7 13.c6 Kb8
14.Kc4 Kc8 15.Kd4 Kd8 16.Kd5 Kc7 17.Kc5H Kb8H
18.Kb6H a4H 19.bxa4H Kc8H 20.Kxa6H Kb8H 21.a5H
{HT} {160}
16768481 26.758 8.00 19. 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kd7
6.Ke5 Kc6 7.Ke6 Kc7 8.Kd5 Kb7 9.Kd6 bxa5
10.Kxc5 Kc7 11.Kd5 Kd7 12.c5 Kc7 13.c6 Kb8
14.Kc4 Kc8 15.Kd4 Kd8 16.Kd5 Kc7 17.Kc5 Kb8
18.Kb6 a4 19.bxa4 Kc8 20.Kxa6 Kb8 21.a5 {HT}
{160}
19175810 30.305 8.00 20t 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kd7
6.Ke5 Kc6 7.Ke6 Kc7H 8.Kd5H bxa5H 9.Kxc5H Kb7H
10.Kd6H a4H 11.bxa4H a5H 12.c5H Kc8H 13.Kc6H
Kd8H 14.Kb6H Kc8H 15.Ka6H Kd8H 16.c6H Ke7H
17.c7H Kd7H {80}
21514125 33.939 8.00 20. 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kd7
6.Ke5 Kc6 7.Ke6 Kc7 8.Kd5 bxa5 9.Kxc5 Kb7
10.Kd6 a4 11.bxa4 a5 12.c5 Kc8 13.Kc6 Kd8
14.Kb6 Kc8 15.Ka6 Kd8 16.c6 Ke7 17.c7 Kd7 {80}
26176734 40.435 8.00 21t 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kd7
6.Ke5 Kc6 7.Ke6 bxa5H 8.Ke5H Kb6H 9.Kd5H Kb7H
10.Kxc5H Kc7H 11.Kd5H Kd7H 12.c5H Kc7H 13.c6H
a4H 14.bxa4H a5H 15.Kc5H Kc8H 16.Kd6H Kd8H
17.Kd5H Ke7H 18.Kc4H Ke8H 19.Kb5H Kd8H 20.Kb6H
Ke7H 21.c7H Kd7H 22.Kb7H Ke6H 23.Kc6H Ke5H
24.c8=QH {1001}
30074196 47.569 8.00 21. 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kd7
6.Ke5 Kc6 7.Ke6 bxa5 8.Ke5 Kb6 9.Kd5 Kb7
10.Kxc5 Kc7 11.Kd5 Kd7 12.c5 Kc7 13.c6 a4
14.bxa4 a5 15.Kc5 Kc8 16.Kd6 Kd8 17.Kd5 Ke7
18.Kc4 Ke8 19.Kb5 Kd8 20.Kb6 Ke7 21.c7 Kd7
22.Kb7 Ke6 23.Kc6 Ke5 24.c8=Q {1001}
31879094 53.253 8.40 22++ 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kd7
6.Ke5 Kc6 7.Ke6 bxa5 8.Ke5 Kb6 9.Kd5 Kb7
10.Kxc5 Kc7 11.Kd5 Kd7 12.c5 Kc7 13.c6 Kd8
14.Kc4 Ke7 15.Kc5 Ke6 16.c7 Kf6 17.Kb6 Kg6
18.c8=Q Kf6
33136176 55.738 9.40 22++ 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kd6 5.Kf5 Kd7
6.Ke5 Kc6 7.Ke6 bxa5 8.Ke5 Kb6 9.Kd5 Kb7
10.Kxc5 Kc7 11.Kd5 Kd8 12.Kd6 Ke8 13.c5 Kf7
14.c6 Kg6 15.c7 a4 16.c8=Q Kh5
56316562 1:25.7 9.42 22t 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kc7H 5.Ke7H
bxa5H 6.Ke6H Kb6H 7.Kd5H Kb7H 8.Kxc5H Kc7H
9.Kd5H Kd7H 10.c5H Kc7H 11.c6H Kd8H 12.Kc4H
Ke7H 13.Kc5H Kf6H 14.c7H a4H 15.c8=QH Kg7H {HT}
61837019 1:34.4 9.42 22. 1.a4 Kd7 2.a5 Kd6 3.Kf7 Kd7 4.Kf6 Kc7 5.Ke7
bxa5 6.Ke6 Kb6 7.Kd5 Kb7 8.Kxc5 Kc7 9.Kd5 Kd7
10.c5 Kc7 11.c6 Kd8 12.Kc4 Ke7 13.Kc5 Kf6 14.c7
a4 15.c8=Q Kg7
In both positions, the found moves are the only winning moves. The PVs look
decent.
Regards,
Dieter
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