Likavsky-Huzman, Quebec op Montreal 2007

[jdart]

[d] 5nk1/2R2pp1/8/1r2PP2/pp6/7P/P5BK/8 w - -

It appears White (Likavsky) could have drawn here with Re7.

Rybka finds this pretty quickly but it's reasonably difficult for my program.

--Jon

[yanquis1972]

by 'pretty quickly' do you mean 'at depth 3 with a score of 0.00 by depth 11 (still at 0 seconds)'? because that's what i'm seeing.

rybka is black magic.

[nevatre]

it is interesting, my program struggles too. It takes a lot of effort to find the draw even after being given Re7. After 1 Re7 b3 2 ab ab the move 3 Re8 is particularly difficult to find for some reason, my program prefers 3 Be4 initially.

15 2.04 5.5 3732665 b4b3 a2b3 a4b3 g2e4 b3b2 h2g2 b5b4 e4b1 b4b6 g2h2 b6b8 e5e6 f7e6 f5e6 f8e6 e7e6
16 2.04 6.3 4330134 b4b3 a2b3 a4b3 g2e4
17 2.01 22.2 15917512 b4b3 a2b3 a4b3 g2e4 b3b2 h2g2 b2b1=Q e4b1 b5b1 g2f3 b1c1 f3e2 c1c3 h3h4 c3c2
18 2.01 29.0 20744428 b4b3 a2b3 a4b3 g2e4
19 1.56 71.0 50439272 ?? b4b3
19 0.18 225.3 156148516 b4b3 a2b3 a4b3 e7e8 g8h7 e8f8 b3b2 g2e4
exit
20 0.18 231.8 160628736 b4b3

FH first(%)=43.0 Evals=95829450 Q. srchs=95829450 H probe=148262868 H store=48469527 H FH=12718726 H FL=3145652 H exact=9662 MNPS= 0.69

[plattyaj]

Interestingly Schola, with it's very basic evaluation, goes for Re7 at ply 3 too but it's still showing a +27 score for white a couple of minutes later.

Andy.

[Eelco de Groot]

[d] 5nk1/2R2pp1/8/1r2PP2/pp6/7P/P5BK/8 w - -

It appears White (Likavsky) could have drawn here with Re7.

Rybka finds this pretty quickly but it's reasonably difficult for my program.

--Jon

A bit late reaction but just in case this ends up as a testposition, I was not sure Re7 is the only move that draws.

I don't know if other programs choose 1. Kg3 like Ancalagon, probably Stockfish does too? I think this move draws, but actually Ancalagon does not agree with me because the score is decreasing slightly, so in the end this makes finding 1. Re7 with close to a draw score easier, but it is found only at 15 ply.

[d]5nk1/2R2pp1/8/1r2PP2/pp6/7P/P5BK/8 w - -

Engine: Ancalagon 1.3 Weak Squares 180 Board Control 50 middlegame -50 endgame Build 185 (Athlon 2009 MHz, 256 MB)
by Romstad, Costalba, Kiiski, de Groot

5.00 0:00 -0.70 1.Re7 b3 2.axb3 axb3 3.Be4 b2 4.Bb1 (521.291) 575

6.01 0:01 -0.84 1.Re7 b3 2.axb3 axb3 3.Be4 b2 4.Bb1 Ra5 (652.709) 605

6.03 0:01 -0.45 1.Kg3 b3 2.axb3 axb3 3.Rb7 Rxb7
4.Bxb7 Kh7 (778.254) 638

7.01 0:02 -0.25 1.Kg3 b3 2.axb3 axb3 3.Rb7 Rxb7
4.Bxb7 Nd7 5.Kf4 (2.055.196) 751

8.01 0:04 -0.39 1.Kg3 b3 2.axb3 axb3 3.Rb7 Rxb7
4.Bxb7 Nd7 5.Kf4 Nc5 (3.415.523) 847

9.01 0:06 -0.09 1.Kg3 b3 2.axb3 axb3 3.Rb7 Rxb7
4.Bxb7 Nd7 5.Kf4 Nc5 6.Bd5 (5.687.848) 896

10.01 0:14 -0.47 1.Kg3 b3 2.axb3 axb3 3.Rc1 g6 4.Kf4 gxf5
5.Kxf5 Ng6 6.Ke4 Rb4+ 7.Ke3 Nxe5 (13.438.024) 919

11.01 0:35 -0.47 1.Kg3 b3 2.axb3 axb3 3.Rc1 g6 4.Kf4 gxf5
5.Kxf5 Ng6 6.Ke4 Rb4+ 7.Ke3 Nxe5 (31.922.526) 894

12.01 1:08 -0.45 1.Kg3 b3 2.axb3 axb3 3.Rc1 Rxe5
4.Rb1 Rxf5 5.Rxb3 Ra5 6.Rb7 g6 7.Be4 Kg7 (61.679.775) 895

13.01 3:04 -0.56 1.Kg3 b3 2.axb3 axb3 3.Be4 Rxe5
4.Kf3 Rb5 5.Ke3 b2 6.Bb1 Rb3+ 7.Kd2 Rxh3
8.Ra7 Rh4 9.Kc3 (162.215.489) 881

14.01 8:15 -0.49 1.Kg3 b3 2.axb3 axb3 3.Be4 Rxe5
4.Kf3 Rb5 5.Ke2 b2 6.Bb1 Rb3 7.Kd2 Rxh3
8.Kc2 Rh2+ 9.Kc3 Re2 (437.068.297) 882

14.21 24:41 -0.31 1.Re7 (1.214.350.784) 819

15.01 25:08 -0.01 1.Re7 b3 2.axb3 axb3 3.Re8 b2 4.Be4 Rb6
5.Bb1 g6 6.e6 fxe6 7.fxg6 Rb7 8.Kg3 Kg7
9.Kf2 Nxg6 10.Rxe6 (1.234.499.316) 818

Two best moves:

5nk1/2R2pp1/8/1r2PP2/pp6/7P/P5BK/8 w - -

Engine: Ancalagon 1.3 WS180BC5050 (256 MB)
by Romstad, Costalba, Kiiski, de Groot

14 6:15 -0.13 1.Re7 b3 2.axb3 axb3 3.Re8 b2 4.Be4 Rb6
5.Bb1 g6 6.e6 fxe6 7.fxg6 Rd6 8.Rb8 Rd2+
9.Kg3 Kg7 10.Rb7+ Nd7 11.Kf4 (321.674.748) 855

14 6:15 -0.43 1.Kg3 b3 2.axb3 axb3 3.Be4 Rxe5
4.Kf4 Rb5 5.Ke3 b2 6.Bb1 g5 7.fxg6 Nxg6
8.Kd4 Kg7 9.Kc4 Rh5 (321.674.748) 855
______________________________________________________________________


15 14:05 -0.13 1.Re7 b3 2.axb3 axb3 3.Re8 b2 4.Be4 Rb6
5.Bb1 g6 6.e6 fxe6 7.fxg6 Rd6 8.Rb8 Rd2+
9.Kg3 Kg7 10.Rb7+ Nd7 11.Kf4 (718.476.336) 849

15 14:05 -0.50 1.Kg3 b3 2.axb3 axb3 3.Be4 Rxe5
4.Kf3 Rb5 5.Ke2 b2 6.Bb1 Rb3 7.Kd2 Rxh3
8.Ra7 Rh5 9.Kc3 Rh2 (718.476.336) 849

Two best moves now after entering 1. Kg3

[d]5nk1/2R2pp1/8/1r2PP2/pp6/6KP/P5B1/8 b - -

Engine: Ancalagon 1.3 WS180BC5050 Build 185 (256 MB)
by Romstad, Costalba, Kiiski, de Groot

13 2:10 +0.47 1...b3 2.axb3 axb3 3.Be4 Rxe5 4.Kf3 Rb5
5.Ke2 b2 6.Bb1 Rb3 7.Kd2 Rxh3 8.Ra7 Rh2+
9.Kc3 Re2 (100.135.728) 765

13 2:10 +0.39 1...Rxe5 2.Kf4 Rb5 3.Bf1 Rd5 4.Rxf7 Kxf7
5.Bc4 Nd7 6.Bxd5+ Kf6 7.Ke4 b3
8.axb3 axb3 9.Kd3 (100.135.728) 765
_______________________________________________________________

14 8:23 +0.56 1...b3 2.axb3 axb3 3.Be4 Rxe5 4.Kf3 Rb5
5.Ke2 b2 6.Bb1 Rb3 7.Kd2 Rxh3 8.Rb7 Rh5
9.Re7 Rh2+ 10.Kc3 (385.866.021) 766

14 8:23 +0.41 1...Rxe5 2.Kg4 Ra5 3.Be4 b3 4.axb3 a3
5.Rc1 Rb5 6.Rc7 g6 7.fxg6 Nxg6 8.Ra7 Rxb3 (385.866.021) 766
_______________________________________________________________

15 17:30 +0.62 1...b3 2.axb3 axb3 3.Be4 Rxe5 4.Kf3 Rb5
5.Ke3 b2 6.Bb1 g5 7.fxg6 Nxg6 8.Kd4 Kg7
9.Kc4 Rh5 10.Rb7 Ne5+ 11.Kd4 (795.523.811) 757

15 17:30 +0.05 1...Rxe5 2.Kf4 Ra5 3.Rc4 b3 4.axb3 a3
5.Rc1 Rb5 6.Rc8 Rxb3 7.Bd5 Rb4+
8.Ke3 Ra4 9.Rc1 Ra5 10.Kd4 Nd7
11.Rc8+ Kh7 12.Bxf7 Rxf5 (795.523.811) 757

best move: Rb5xe5 time: 30:05.047 min n/s: 724.202 nodes: 1.307.220.212

Score here seems to go up slightly for Black after 1. Kg3 b3.

If it is not a draw then 1. Kg3 is just a bad move, and finding Re7 only after 24 minutes is not such a good performance from Ancalagon.

Analysis with Rybka 2.2n2 in a position a few moves further however pointed to a draw, and Rybka was using 5 men tablebases that may have been of some use. The first, skipped, moves seem okay, agreeing with the PV above:

Rybka after

[FEN "5nk1/2R2pp1/8/1r2PP2/pp6/7P/P5BK/8 w - -"]

1. Kg3 b3 2. axb3 axb3 3. Be4 Rxe5 *


[d]5nk1/2R2pp1/8/4rP2/4B3/1p4KP/8/8 w - -

Engine: Rybka 2.2n2 mp 32-bit PVtips5menbasesSO (128 MB)
by Vasik Rajlich

11.01 0:00 -0.73 4.Kf3 Rb5 5.Ke2 b2 6.Bb1 g6 7.fxg6 Nxg6
8.Kd2 Nf4 9.h4 Kg7 10.Kc2 Nd5 11.Rd7 Ne3+
12.Kc3 Kf6 (88.188) 148

12.01 0:00 -0.68 4.Kf3 Rb5 5.Ke2 b2 6.Bb1 g6 7.fxg6 Nxg6
8.Kd2 Nf4 9.h4 Kg7 10.Kc2 Nd5 11.Rd7 Ne3+
12.Kc3 Kf6 (136.106) 156

13.01 0:01 -0.68 4.Kf3 Rb5 5.Ke2 b2 6.Bb1 g6 7.fxg6 Nxg6
8.Kd2 Nf4 9.h4 Kg7 (201.711) 161

14.01 0:02 -0.65 4.Kf3 Rb5 5.Ke2 b2 6.Bb1 g6 7.fxg6 Nxg6
8.Kd2 Nf4 9.h4 Kg7 10.Ra7 Kf6 (306.773) 153

15.01 0:03 -0.59 4.Kf3 Rb5 5.Ke2 b2 6.Bb1 g6 7.fxg6 Nxg6
8.Kd2 Nf4 9.h4 Kg7 10.Ra7 Kf6 (500.561) 146

16.01 0:06 -0.47 4.Kf3 Rb5 5.Ke2 b2 6.Bb1 g6 7.fxg6 Nxg6
8.Kd2 Nf4 9.h4 Kg7 10.Ra7 Kf6 (870.390) 132

17.01 0:10 -0.50 4.Kf3 Rb5 5.Ke2 b2 6.Bb1 g6 7.fxg6 Nxg6
8.Kd2 Nf4 (1.350.757) 129

18.01 0:17 -0.47 4.Kf3 Rb5 5.Ke2 b2 6.Bb1 g6 7.fxg6 Nxg6
8.Kd2 Nf4 (2.169.093) 123

19.01 0:40 -0.38 4.Kf3 Rb5 5.Ke2 b2 6.Bb1 g6 7.fxg6 Nxg6
8.Kd2 Nf4 (4.451.507) 113

20.01 1:29 -0.39 4.Kf3 Rb5 5.Ke3 b2 6.Bb1 g6 7.fxg6 Nxg6
8.Ra7 Kg7 9.Ra2 Ne5 10.Kd4 f5
11.Bxf5 Nf3+ 12.Kc3 Rxf5 13.Rxb2 Ne5
14.Rg2+ Kf8 15.Kc2 Nd7 16.h4 (9.992.551) 113

21.01 4:10 -0.32 4.Kf3 Rb5 5.Ke3 b2 6.Bb1 g6 7.fxg6 Nxg6
8.Ra7 Kf8 9.Kd2 f5 10.Kc3 Ne7 11.Ra3 f4
12.Rb3 Rxb3+ 13.Kxb3 f3 (30.953.098) 126

22.01 5:35 -0.33 4.Kf3 Rb5 5.Ke3 b2 6.Bb1 g6 7.fxg6 Nxg6
8.Ra7 Kf8 9.Kd2 f5 10.Kc3 Ne7 11.Kc4 Rb6
12.Ra3 f4 13.Rb3 Nd5 (40.620.560) 123

23.01 8:23 -0.38 4.Kf3 Rb5 5.Ke3 b2 6.Bb1 Rb8 7.Kd3 Nh7 (61.661.508) 125

24.01 12:06 -0.40 4.Kf3 Rb5 5.Ke3 b2 6.Bb1 Rb8 7.Kd3 Nh7 (93.156.220) 131

25.01 18:22 -0.40 4.Kf3 Rb5 5.Ke3 b2 6.Bb1 Rb8 7.Kd3 Nh7 (143.914.384) 133

26.01 29:25 -0.45 4.Kf3 Rb5 5.Ke3 b2 6.Bb1 Rb8 7.Kd3 Nh7 (236.008.413) 136

26.02 133:03 -0.20 4.Kf4 Rb5 5.Rc8 b2 6.Bb1 g6 7.fxg6 fxg6
8.Rc3 Ne6+ 9.Ke3 Kg7 10.Kd3 g5
11.Kc4 Rc5+ 12.Kb3 Rxc3+ 13.Kxc3 Nf4
14.Kxb2 Kf6 15.Be4 Nxh3 16.Bf3 Kf5 (1.253.870.914) 160

27.01 161:18 -0.19 4.Kf4 Rb5 5.Rc8 b2 6.Bb1 g6 7.fxg6 fxg6
8.Rc3 Ne6+ 9.Ke3 Kg7 10.Kd3 g5
11.Kc4 Rc5+ 12.Kb3 Rxc3+ 13.Kxc3 Nf4
14.Kxb2 Kf6 15.Be4 Nxh3 16.Bf3 Kf5 (1.435.893.716) 151

28.01 182:05 -0.20 4.Kf4 Rb5 5.Rc8 b2 6.Bb1 g6 7.fxg6 fxg6
8.Rc3 Ne6+ 9.Ke3 Kg7 10.Kd3 g5
11.Kc4 Rc5+ 12.Kb3 Rxc3+ 13.Kxc3 Nf4
14.Kxb2 Kf6 15.Be4 Nxh3 16.Bf3 Kf5
17.Kc3 (1.589.812.197) 149

29.01 257:45 -0.20 4.Kf4 Rb5 5.Rc8 f6 6.h4 g6 7.fxg6 Kg7
8.Rc7+ Kh6 9.Ke3 Nxg6 10.Rb7 Rxb7
11.Bxb7 Nxh4 12.Kd2 f5 13.Kc3 (2.099.818.403) 139

best move: Kg3-f4 time: 267:21.828 min n/s: 2147.483.647 nodes: 2.192.636.079

[beachknight]

H: 512 MB
TB: 3,4,5 complete

1567: 5nk1/2R2pp1/8/1r2PP2/pp6/7P/P5
5nk1/2R2pp1/8/1r2PP2/pp6/7P/P5BK/8 w - - 0 1

Analysis by Deep Fritz 11:

1.Bf1 Rxe5 2.Bc4 Rxf5 3.Kg3 g5 4.Kg4 Rf2 5.Kxg5 Ne6+ 6.Bxe6 fxe6 7.Rb7 Rxa2 8.Rxb4 Rg2+ 9.Kf6 a3 10.Ra4 a2 11.Kxe6 Kg7 12.Ke5 Rh2 13.h4
=/+ (-0.40) Depth: 24/36 00:00:42 292mN, tb=2291
1.Rc8 Rxe5 2.Rb8 b3 3.axb3 axb3 4.Bf1 Rxf5 5.Bc4 g6 6.Bxb3 Rf2+ 7.Kg3 Rd2 8.h4 Rd3+ 9.Kf4 Kg7 10.Rb5 Rd4+ 11.Kg3 Nd7 12.Rd5 Rxd5
=/+ (-0.40) Depth: 24/39 00:01:27 549mN, tb=9236
1.Rc8 Rxe5 2.Rb8 b3 3.axb3 axb3 4.Bf1 Rxf5 5.Bc4 g6 6.Bxb3 Rf2+ 7.Kg3 Rd2 8.h4 Rd3+ 9.Kf4 Kg7 10.Rb5 Nd7 11.Rd5 Rxd5 12.Bxd5 Nc5 13.Bc4 Kf6
=/+ (-0.39) Depth: 25/43 00:01:59 788mN, tb=11678
1.Rc8 Rxe5 2.Rb8 b3 3.axb3 axb3 4.Bf1 Rxf5 5.Bc4 g6 6.Bxb3 Rf2+ 7.Kg3 Rd2 8.h4 Rd3+ 9.Kf4 Kg7 10.Rb5 Rd4+ 11.Kg3 Nd7 12.Rd5 Rxd5 13.Bxd5 Kf6 14.Kf4
=/+ (-0.38) Depth: 26/43 00:03:00 1179mN, tb=20665
1.Re7 b3 2.axb3 axb3 3.Re8 b2 4.Be4 Rb6 5.Bd3 Rb3 6.Bb1 Re3 7.Rb8 Rxe5 8.Rxb2 Nd7 9.Rb7 Re1 10.Bd3 Ne5 11.Bb5 Nf3+ 12.Kg2 Nh4+
= (0.07) Depth: 26/55 00:05:34 1973mN, tb=59481
1.Re7 b3 2.axb3 axb3 3.Re8 b2 4.Be4 Rb6 5.Bd3 g5 6.e6 fxe6 7.fxe6 Rxe6 8.Rb8 Re3 9.Bc4+ Kh7 10.Rxb2 Ng6 11.Rb7+ Kh6 12.Rb8 Nf4 13.Rb6+ Kg7 14.Rb7+ Kf6
= (0.00) Depth: 27/47 00:06:36 2422mN, tb=70711

(, chessengines20 18.07.2009)