Endgame test position

[MikeGL]

b7/5k2/pr2p1pr/Pp1pPpPp/1PpP1P1P/2P5/8/B3K3 w - - 0 1

RBRKQRBn/PpPPPPpP/8/8/8/8/8/5B1k w - - 0 1
White to play and draw.

BNRRN2b/5Kpr/5np1/6pr/6pq/6pk/6p1/6Bb w - - 3 3
White to play and win.

Very easy for humans,
but all my engine collections won't agree with my lines.

[d]RBRKQRBn/PpPPPPpP/8/8/8/8/8/5B1k w - - 0 1

1.Bg2+ only move which draws,
all other B moves will allow black to promote to N at either b1 or g1, and deliver mate at Nb7# Nc6# Ne6#.

[d] BNRRN2b/5Kpr/5np1/6pr/6pq/6pk/6p1/6Bb w - - 3 3
White to play and win.

I guess just position both R at c3 and c4 respectively,
then bring both white N to f2 and another at f3 to deliver mate.
But there might be more efficient lines to deliver mate on this position.

[MikeGL]

[d] b7/5k2/pr2p1pr/Pp1pPpPp/1PpP1P1P/2P5/8/B3K3 w - - 0 1
White to play and draw.

Deep Shredder

32/43 0:01 -0.18 1.Bb2 Rh7 2.Kf2 Rb8 3.Bc1 Ke7 4.Ke2 Rc8 5.Be3 Bc6 6.Kd2 Rhh8 7.Ke2 Ba8 (17.797.885) 12265
33/44 0:02 -0.18 1.Bb2 Rh7 2.Kf2 Rb8 3.Bc1 Ke7 4.Ke2 Rc8 5.Be3 Bc6 6.Kd2 Rhh8 7.Ke2 Ba8 (25.098.692) 12376
34/45 0:02 -0.18 1.Bb2 Rh7 2.Kf2 Rb8 3.Bc1 Ke7 4.Ke2 Rc8 5.Be3 Bc6 6.Kd2 Rhh8 7.Ke2 Ba8 (36.554.421) 12463
35/44 0:04 -0.18 1.Bb2 Rh7 2.Kf2 Rb8 3.Bc1 Ke7 4.Ke2 Rc8 5.Be3 Bc6 6.Kd2 Rhh8 7.Ke2 Ba8 (60.943.544) 12723
36/48 0:07 -0.18 1.Bb2 Rh7 2.Kf2 Rb8 3.Bc1 Ke7 4.Ke2 Rc8 5.Be3 Bc6 6.Kd2 Rhh8 7.Ke2 Ba8 (94.514.866) 12753
37/49 0:10 -0.18 1.Bb2 Rh7 2.Kf2 Rb8 3.Bc1 Ke7 4.Ke2 Rc8 5.Be3 Bc6 6.Kd2 Rhh8 7.Ke2 Ba8 (136.391.453) 12838
38/51 0:16 -0.18 1.Bb2 Rh7 2.Kf2 Rb8 3.Bc1 Ke7 4.Ke2 Rc8 5.Be3 Bc6 6.Kd2 Rhh8 7.Ke2 Ba8 (216.624.451) 12952
39/53 0:26 -0.18 1.Bb2 Rh7 2.Kf2 Rb8 3.Bc1 Ke7 4.Ke2 Rc8 5.Be3 Bc6 6.Kd2 Rhh8 7.Ke2 Ba8 (340.436.944) 13005
40/53 0:43 -0.18 1.Bb2 Rh7 2.Kf2 Rb8 3.Bc1 Ke7 4.Ke2 Rc8 5.Be3 Bc6 6.Kd2 Rhh8 7.Ke2 Ba8 (570.408.903) 13095
41/41 1:18 -0.18 1.Bb2 Rh7 2.Kf2 Rb8 3.Bc1 Ke7 4.Ke2 Rc8 5.Be3 Bc6 6.Kd2 Rhh8 7.Ke2 Ba8 (1.031.575.015) 13188
42/57 2:19 -0.18 1.Bb2 Rh7 2.Kf2 Rb8 3.Bc1 Ke7 4.Ke2 Rc8 5.Be3 Bc6 6.Kd2 Rhh8 7.Ke2 Ba8 (1.828.464.668) 13111

Strange. It seems Deep Shredder "understands" the position.
But the line is not correct.
I think moving one of the Rooks is not the best move. If black wants
to, at least, try to win then it must entice white into capturing one of its Rooks to open up the position and win. Hence, moving one of the rooks is not the best move for black. Black can only move a rook when white captures one of them.

[kgburcham]

[d] BNRRN2b/5Kpr/5np1/6pr/6pq/6pk/6p1/6Bb w - - 3 3
White to play and win.

6 processor(s) found, POPCNT available
NUMA configuration with 1 node(s), offset 0
4096 MB Large Page Hash
Nalimov 6 men EGTB available - 999 MB cache
Houdini 2.0c Pro x64 (4096 MB)

36/82 4:55 0.00 1.Ke6 R5h6 2.Nd6 Nh5 3.Rc2 Nf4+ 4.Kd7 Nd3 5.Re8 Nf4 (5.961.823.422) 20168
36/82 5:12 +0.06++ 1.Nd6 (6.281.252.121) 20086
36/82 5:16 +0.18++ 1.Nd6 (6.329.890.179) 20028
36/82 5:29 +0.45++ 1.Nd6 (6.535.327.848) 19851
36/82 7:19 +1.46++ 1.Nd6 (8.425.301.318) 19156 TB:8
36/83 12:23 +5.27++ 1.Nd6 (13.848.302.149) 18635 TB:91
36/83 18:13 +15.30++ 1.Nd6 (21.467.949.071) 19627 TB:122
36/83 20:06 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 (24.257.173.033) 20109 TB:122
37/83 22:13 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 (27.543.277.088) 20658 TB:122
38/83 22:52 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 (28.602.730.878) 20847 TB:122
39/83 23:47 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 (30.102.324.809) 21081 TB:122
40/83 25:08 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 7.Nxg3 Kh3 8.Nf5+ g3 9.Rxg3+ (32.296.882.164) 21414 TB:122

[kgburcham]

[d] BNRRN2b/5Kpr/5np1/6pr/6pq/6pk/6p1/6Bb w - - 3 3
White to play and win.

6 processor(s) found, POPCNT available
NUMA configuration with 1 node(s), offset 0
4096 MB Large Page Hash
Nalimov 6 men EGTB available - 999 MB cache
Houdini 2.0c Pro x64 (4096 MB)

36/82 4:55 0.00 1.Ke6 R5h6 2.Nd6 Nh5 3.Rc2 Nf4+ 4.Kd7 Nd3 5.Re8 Nf4 (5.961.823.422) 20168
36/82 5:12 +0.06++ 1.Nd6 (6.281.252.121) 20086
36/82 5:16 +0.18++ 1.Nd6 (6.329.890.179) 20028
36/82 5:29 +0.45++ 1.Nd6 (6.535.327.848) 19851
36/82 7:19 +1.46++ 1.Nd6 (8.425.301.318) 19156 TB:8
36/83 12:23 +5.27++ 1.Nd6 (13.848.302.149) 18635 TB:91
36/83 18:13 +15.30++ 1.Nd6 (21.467.949.071) 19627 TB:122
36/83 20:06 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 (24.257.173.033) 20109 TB:122
37/83 22:13 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 (27.543.277.088) 20658 TB:122
38/83 22:52 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 (28.602.730.878) 20847 TB:122
39/83 23:47 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 (30.102.324.809) 21081 TB:122
40/83 25:08 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 7.Nxg3 Kh3 8.Nf5+ g3 9.Rxg3+ (32.296.882.164) 21414 TB:122

12 threads
HT off
Houdini 2.0c Pro x64:

1.Nd6
= (0.05 ++) Depth: 26/77 00:00:03 61466kN
1.Nd6
= (0.18 ++) Depth: 26/77 00:00:03 64223kN
1.Nd6
+/= (0.45 ++) Depth: 26/77 00:00:03 76300kN
1.Nd6
+- (1.45 ++) Depth: 26/77 00:00:04 103mN
1.Nd6
+- (5.26 ++) Depth: 26/77 00:00:06 146mN
1.Nd6
+- (15.30 ++) Depth: 26/77 00:00:08 230mN
1.Nd6 R5h6 2.Rc3 Qh5 3.Ke6 Qh4 4.Nc6 Qh5 5.Ra3 Qh4 6.Ne5 Qh5 7.Nd3 Kh4 8.Nf7 Ne4 9.Bxe4 Kh3 10.Rd4 Kh4 11.Bf3 Kh3 12.Nf2+ Kh4 13.Bd1 gxf2 14.Bxf2#
+- (#14) Depth: 26/78 00:00:10 293mN
1.Nd6 R5h6 2.Rc3 Qh5 3.Ke6 Qh4 4.Nc6 Qh5 5.Ra3 Qh4 6.Ne5 Qh5 7.Nd3 Kh4 8.Nf7 Ne4 9.Bxe4 Kh3 10.Rd4 Kh4 11.Bf3 Kh3 12.Nf2+ Kh4 13.Bd1 gxf2 14.Bxf2#
+- (#14) Depth: 27/78 00:00:10 305mN
1.Nd6 R5h6 2.Rc3 Qh5 3.Ke6 Qh4 4.Nc6 Qh5 5.Ra3 Qh4 6.Ne5 Qh5 7.Nd3 Kh4 8.Nf7 Ne4 9.Bxe4 Kh3 10.Rd4 Kh4 11.Bf3 Kh3 12.Nf2+ Kh4 13.Bd1 gxf2 14.Bxf2#
+- (#14) Depth: 28/78 00:00:11 332mN
1.Nd6 R5h6 2.Rc3 Qh5 3.Ke6 Qh4 4.Nc6 Qh5 5.Ra3 Qh4 6.Ne5 Qh5 7.Nd3 Kh4 8.Nf7 Ne4 9.Bxe4 Kh3 10.Rd4 Kh4 11.Bf3 Kh3 12.Nf2+ Kh4 13.Bd1 gxf2 14.Bxf2#
+- (#14) Depth: 29/78 00:00:13 400mN
1.Nd6 R5h6 2.Rc3 Qh5 3.Ke6 Qh4 4.Nc6 Qh5 5.Ra3 Qh4 6.Ne5 Qh5 7.Nd3 Kh4 8.Nf7 Ne4 9.Bxe4 Kh3 10.Rd4 Kh4 11.Bf3 Kh3 12.Nf2+ Kh4 13.Bd1 gxf2 14.Bxf2#
+- (#14) Depth: 30/78 00:00:16 507mN
1.Nd6 R5h6 2.Rc3 Qh5 3.Ke6 Qh4 4.Nc6 Qh5 5.Ne5 Qh4 6.Nd3 Qh5 7.Nf2+ Kh4 8.Nde4 Nxe4 9.Nxe4 Kh3 10.Nf2+ Kh4 11.Rd4 gxf2 12.Bxf2#
+- (#12) Depth: 31/78 00:00:22 732mN
1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Kh4 4.Nc5 Nd5 5.Bxd5 Kh3 6.Nde4 Kh4 7.Nxg3 Kh3 8.Nf5+ g3 9.Rxg3#
+- (#9) Depth: 32/78 00:00:31 1043mN
1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Kh4 4.Nc5 Nd5 5.Bxd5 Kh3 6.Nde4 Kh4 7.Nxg3 Kh3 8.Nf5+ g3 9.Rxg3#
+- (#9) Depth: 33/78 00:00:35 1201mN
1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Kh4 4.Nc5 Nd5 5.Bxd5 Kh3 6.Nde4 Kh4 7.Nxg3 Kh3 8.Nf5+ g3 9.Rxg3#
+- (#9) Depth: 34/78 00:00:43 1476mN
1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Kh4 4.Nc5 Nd5 5.Bxd5 Kh3 6.Nde4 Kh4 7.Nxg3 Kh3 8.Nf5+ g3 9.Rxg3#
+- (#9) Depth: 35/78 00:00:53 1836mN
1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Kh4 4.Nc5 Nd5 5.Bxd5 Kh3 6.Nde4 Kh4 7.Nxg3 Kh3 8.Nf5+ g3 9.Rxg3#
+- (#9) Depth: 36/78 00:01:08 2401mN

[kgburcham]

[d] RBRKQRBn/PpPPPPpP/8/8/8/8/8/5B1k w - - 0 1
White to play and draw.

Houdini 2.0c Pro x64:

1.Bd3 b6
= (-0.05 --) Depth: 43/78 00:00:44 1121mN
1.Bg2+ Kxg2
= (0.00) Depth: 43/78 00:00:48 1224mN
1.Bg2+ Kxg2
= (0.00) Depth: 44/78 00:00:50 1276mN
1.Bg2+ Kxg2
= (0.00) Depth: 45/78 00:00:53 1341mN
1.Bg2+ Kxg2
= (0.00) Depth: 46/78 00:00:57 1455mN
1.Bg2+ Kxg2
= (0.00) Depth: 47/78 00:01:05 1686mN
1.Bg2+ Kxg2
= (0.00) Depth: 48/84 00:01:13 1889mN
1.Bg2+ Kxg2
= (0.00) Depth: 49/84 00:01:35 2612mN
1.Bg2+ Kxg2
= (0.00) Depth: 50/85 00:01:57 3310mN

[kgburcham]

[d] BNRRN2b/5Kpr/5np1/6pr/6pq/6pk/6p1/6Bb w - - 3 3
White to play and win.

6 processor(s) found, POPCNT available
NUMA configuration with 1 node(s), offset 0
4096 MB Large Page Hash
Nalimov 6 men EGTB available - 999 MB cache
Houdini 2.0c Pro x64 (4096 MB)

36/82 4:55 0.00 1.Ke6 R5h6 2.Nd6 Nh5 3.Rc2 Nf4+ 4.Kd7 Nd3 5.Re8 Nf4 (5.961.823.422) 20168
36/82 5:12 +0.06++ 1.Nd6 (6.281.252.121) 20086
36/82 5:16 +0.18++ 1.Nd6 (6.329.890.179) 20028
36/82 5:29 +0.45++ 1.Nd6 (6.535.327.848) 19851
36/82 7:19 +1.46++ 1.Nd6 (8.425.301.318) 19156 TB:8
36/83 12:23 +5.27++ 1.Nd6 (13.848.302.149) 18635 TB:91
36/83 18:13 +15.30++ 1.Nd6 (21.467.949.071) 19627 TB:122
36/83 20:06 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 (24.257.173.033) 20109 TB:122
37/83 22:13 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 (27.543.277.088) 20658 TB:122
38/83 22:52 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 (28.602.730.878) 20847 TB:122
39/83 23:47 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 (30.102.324.809) 21081 TB:122
40/83 25:08 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Nd7 5.Rxd7 Qh5 6.Nde4 Kh4 7.Nxg3 Kh3 8.Nf5+ g3 9.Rxg3+ (32.296.882.164) 21414 TB:122

6 processor(s) found, POPCNT available
NUMA configuration with 1 node(s), offset 0
4096 MB Large Page Hash
Nalimov 6 men EGTB available - 999 MB cache
Houdini 2.0c Pro x64 (4096 MB)

27/76 0:10 -0.07++ 1.Rd4 (208.779.872) 20038
27/76 0:11 -0.13 1.Rd4 R5h6 2.Nd6 Nh5 3.Rc3 Nf6 4.Rcd3 Qh5 5.Rc4 Qh4 (227.407.897) 20264
27/76 0:12 +0.04++ 1.Rd3 (255.125.536) 20421
27/76 0:13 +0.32++ 1.Rd3 (266.822.648) 20281
27/76 0:15 +1.25++ 1.Rd3 (300.134.308) 19897
27/76 0:30 +5.02++ 1.Rd3 (638.767.503) 21027
27/76 0:36 +15.09++ 1.Rd3 (758.802.588) 20975
27/83 0:40 +M12 1.Rd3 R5h6 2.Nd6 Qh5 3.Rc4 Qh4 4.Ne4 Nxe4 (865.902.376) 21408
28/83 0:41 +M12 1.Rd3 R5h6 2.Nd6 Qh5 3.Rc4 Qh4 4.Ne4 Nxe4 (896.121.171) 21540
29/83 0:45 +M10 1.Rd3 R5h6 2.Nd6 Qh5 3.Nb5 Ne4 4.Bxe4 Qh4 (983.253.231) 21724
30/83 0:48 +M10 1.Rd3 R5h6 2.Nd6 Qh5 3.Nb5 Ne4 4.Bxe4 Qh4 (1.053.193.744) 21923
31/83 0:52 +M10 1.Rd3 R5h6 2.Nd6 Qh5 3.Nb5 Ne4 4.Bxe4 Qh4 (1.166.739.267) 22248
31/83 0:57 +M10 1.Rd3 R5h6 2.Nd6 Qh5 3.Nb5 Ne4 4.Bxe4 Qh4 5.Nd6 Rh5 6.Rcc3 R5h6 7.Ba8 Qh5 8.Rxg3+ Kh4 9.Bf2 g1R 10.Rh3+ (1.293.931.074) 22576

[kgburcham]

[d] BNRRN2b/5Kpr/5np1/6pr/6pq/6pk/6p1/6Bb w - - 3 3
White to play and win.

Houdini
12 threads
HT off
multi pv

32 2:18 +M9 1.Nd6 R5h6 2.Rc3 Qh5 3.Nd7 Qh4 4.Nc5 Qh5 (5.694.376.014) 41225
32 2:18 +M9 1.Rc3 R7h6 2.Nd7 Ne4 3.Bxe4 Rh7 4.Ba8 R5h6 (5.694.376.014) 41225
32 2:18 +M11 1.Rd7 R5h6 2.Nd6 Rh5 3.Rc3 R7h6 4.Rd8 Rh7 (5.694.376.014) 41225
32 2:18 +M11 1.Rd3 R7h6 2.Rcd8 Rh7 3.Nd6 R5h6 4.Rc3 Qh5 (5.694.376.014) 41225
31 2:18 +M11 1.Rc7 R5h6 2.Rc3 Nh5 3.Nd6 Nf4 4.Ne4 Qh5 (5.694.376.014) 41225
31 2:18 +M11 1.Rc5 R5h6 2.Rc3 Nh5 3.Nd6 Nf4 4.Ne4 Qh5 (5.694.376.014) 41225
31 2:18 +M11 1.Rc4 R5h6 2.Rc3 Nh5 3.Nd6 Nf4 4.Ne4 Qh5 (5.694.376.014) 41225
31 2:18 +M11 1.Rc2 R7h6 2.Rc3 Rh7 3.Nd6 R7h6 4.Nd7 Rh7 (5.694.376.014) 41225
31 2:18 +M11 1.Rc1 R7h6 2.Rc3 Rh7 3.Nd6 R7h6 4.Nd7 Rh7 (5.694.376.014) 41225
31 2:18 +M11 1.Nd7 R5h6 2.Rc3 Nh5 3.Nc5 Nf4 4.Ne4 Qh5 (5.694.376.014) 41225
31 2:18 +M11 1.Na6 R5h6 2.Rc3 Nh5 3.Nc5 Nf4 4.Ne4 Qh5 (5.694.376.014) 41225
31 2:18 +M11 1.Bb7 R7h6 2.Rc3 Rh7 3.Nd6 R7h6 4.Nd7 Rh7 (5.694.376.014) 41225
31 2:18 +M11 1.Kf8 R5h6 2.Nd6 Nh5 3.Rc3 Nf6 4.Kf7 Qh5 (5.694.376.014) 41225
31 2:18 +M12 1.Rd4 R5h6 2.Nd6 Rh5 3.Rc3 R5h6 4.Ne4 Nxe4 (5.694.376.014) 41225
31 2:18 +M13 1.Bd5 R5h6 2.Rc3 Nh5 3.Nd6 Nf4 4.Ne4 Qh5 (5.694.376.014) 41225
31 2:18 +M13 1.Ke7 R5h6 2.Rc3 Nh5 3.Nd6 Nf4 4.Ne4 Qh5 (5.694.376.014) 41225
31 2:18 +M13 1.Rd2 R5h6 2.Nd6 Nh5 3.Rc3 Nf6 4.Re2 Qh5 (5.694.376.014) 41225
31 2:18 +M13 1.Rd1 R5h6 2.Nd6 Nh5 3.Rc3 Nf6 4.Re1 Qh5 (5.694.376.014) 41225

[Jack Lad]

[d] BNR1N2b/5Kpr/5np1/6pr/6pq/6pk/6p1/6Bb w - - 0 1
White can still win without the rook on d8!

[Jack Lad]

Thanks for sharing, Steve

The position is from a study by Korolkov 1948 except with two extra pawns on a2 & a6 which makes it a bit deeper for engines - after a5 white simply plays a4.