The horizon effect

[Jack Lad]

[d] 8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - 0 1
White to play and win.

Fruit cannot see the winning move due to the horizon effect - how about your engine?

[kgburcham]

here is one. thanks for the test position. I will try fire and some others, but only a few programs can run twelve threads.

[D] 8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - -

CPU0: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU1: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU2: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU3: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU4: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU5: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU6: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU7: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU8: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU9: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU10: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU11: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
GUI: Tablebases with 0 pieces found! [Cache: 1 MB + internal 0.00 MB]
GUI: Shredderbases with 0 pieces found (0 MB)
Children restarted.
Hash size set to 4096 mb
Nalimov path set to <empty>
Nalimov cache set to 1
Limited strength mode disabled.
Engine: Deep Rybka 4 SSE42 x64 (4096 MB)
by Vasik Rajlich
Use large pages enabled.
Using large pages, size = 4294967296
Children restarted.
16.00 0:00 -1.99 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 e2 4.Bxe2 c4 5.Bxc4 Nc5 6.Ne3 Ba5+ 7.Ke7 Bc7 8.Kf6 Bxg3 9.Be2 Bf4 10.Nc2 Bb8 (775.062) 1238
17.00 0:00 -2.12 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 e2 4.Bxe2 c4 5.Bxc4 Nc5 6.Ne3 Ba5+ 7.Ke7 Kg6 8.Kd6 Ne4+ 9.Ke5 Nxg3 10.Kf4 Nh5+ (1.209.037) 1267
18.01 0:02 -2.26 1.d8Q Nf7+ 2.Kd7 Nxd8 3.Kxd8 e2 4.Bxe2 c4 5.Bxc4 Nc5 6.Ne3 Ba5+ 7.Kc8 Kg6 8.Ba2 Kg5 9.Bb1 Nb3 10.Kb7 Nd4 (2.774.562) 1354
19.01 0:03 -2.14++ 1.d8Q Nf7+ 2.Kd7 Nxd8 3.Kxd8 e2 4.Bxe2 c4 5.Bxc4 Nc5 6.Ne3 Ba5+ 7.Kc8 Kg6 8.Ba2 Kg5 9.Bb1 Nb3 10.Kd7 Bb6 (4.489.687) 1387
19.01 0:03 -2.16 1.d8Q Nf7+ 2.Kd7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 Bc7 5.Nxe3 Bxg3 6.Kc6 Nb8+ 7.Kb5 Kg6 8.Nd5 Be5 (5.192.832) 1356
20.01 0:05 -2.16 1.d8Q Nf7+ 2.Kd7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 Bc7 5.Nxe3 Bxg3 6.Kc6 Nb8+ 7.Kb5 Kg6 8.Nd5 Be5 9.Kxc5 h5 10.Kc4 h4 (6.881.503) 1371
21.01 0:07 -2.26 1.d8Q Nf7+ 2.Kd7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 Bc7 5.Nxe3 Bxg3 6.Kc6 Kg6 7.Kb6 Nc7 8.Bc2+ Kf6 9.Nf5 Bf4 10.Kxc5 h5 (10.819.792) 1387
21.03 0:12 -2.04++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Nf7+ 5.Ke6 Nxd8+ 6.Kf5 (17.081.981) 1410
21.01 0:12 -1.89++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Nf7+ 5.Ke6 Nxd8+ 6.Kf5 (17.224.829) 1404
21.01 0:12 -1.49++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Nf7+ 5.Ke6 Nxd8+ 6.Kf5 (17.841.732) 1387
21.01 0:13 -0.69++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Nf7+ 5.Ke6 Nxd8+ 6.Kf5 (18.246.848) 1380
21.01 0:14 +0.91++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Nf7+ 5.Ke6 Nxd8+ 6.Kf5 (19.906.524) 1375
21.01 1:17 +4.11++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Nf7+ 5.Ke6 (113.996.046) 1461
21.01 4:05 +6.05 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Bd1+ Kxg3 6.Qe8 c4+ 7.Kc6 Kf4 8.Qg8 Ne4 9.Qxc4 Nac5 10.Kd5 Ba3 (377.730.168) 1537
22.01 4:27 +6.05 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Bd1+ Kxg3 6.Qe8 c4+ 7.Kc6 Kf4 8.Qg8 Ne4 9.Qxc4 Nac5 10.Kd5 Ba3 (408.898.868) 1526
22.01 4:44 +6.05 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Bd1+ Kxg3 6.Qe8 c4+ 7.Kc6 Kf4 8.Qg8 Ne4 (435.041.075) 1527
best move: Ng4-f6 time: 4:45.515 min n/s: 1.527.462 nodes: 435.041.075

[kgburcham]

[D] 8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - -

CPU0: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU1: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU2: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU3: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU4: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU5: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU6: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU7: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU8: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU9: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU10: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
CPU11: GenuineIntel Intel64 Family 6 Model 44 Stepping 0 4301 MHz
GUI: Tablebases with 0 pieces found! [Cache: 1 MB + internal 0.00 MB]
GUI: Shredderbases with 0 pieces found (0 MB)
loading shredderbase C:\Users\kb\AppData\Roaming\ShredderChess\Shredderbases\\all34.tbe
shredderbases with 4 pieces found (1 MB)
128 MB Hash allocated
4096 MB Hash allocated
HT off
window unit set to 68

Engine: Houdini DEVEL x64 POPCNT 12_CPU (4096 MB)
by Robert Houdart
15/38 0:00 -2.25 1.Kc6 Nb8+ 2.Kc7 Nxd7 3.Kxd7 e2 4.Bxe2 Kg7 5.Bd1 Ne4 6.Ke6 Nxg3 7.Ke5 Nf1 8.Ke4 h5 9.Ne3 Nd2+ 10.Kd3 Kg6 11.Nd5 (4.009.508) 5922
16/38 0:00 -2.14++ 1.Kc6 Nb8+ 2.Kc7 Nxd7 3.Kxd7 e2 4.Bxe2 Kg7 5.Bd1 Ne4 6.Ke6 Nxg3 7.Ke5 Nf1 8.Ke4 h5 9.Ne3 Nd2+ 10.Kd3 Kg6 11.Nd5 (4.254.087) 5941
16/38 0:00 -2.07 1.Kc6 Nb8+ 2.Kc7 Nxd7 3.Kxd7 e2 4.Bxe2 Kg7 5.Bd1 Ne4 6.Ke6 Nxg3 7.Ke5 Nf1 8.Ke4 Kg6 9.Ne3 Ng3+ 10.Kf3 Nh5 (4.391.173) 5934
17/40 0:01 -2.27 1.Kc6 Nb8+ 2.Kc7 Nxd7 3.Kxd7 e2 4.Bxe2 Kg7 5.Bd1 Ne4 6.Ke6 Nxg3 7.Ke5 h5 8.Ne3 Kg6 9.Kf4 h4 10.Kg4 Kf6 (7.686.062) 6071
17/40 0:01 -1.97++ 1.d8Q Nf7+ 2.Kd5 Nxd8 3.Nxe3 Nb8 (9.791.890) 6112
17/49 0:01 -1.76++ 1.d8Q Nf7+ 2.Kd5 Nxd8 3.Nxe3 Nb8 (11.206.081) 6229
17/49 0:02 -1.34 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 e2 5.Bxe2 Nb4 6.Ne3 Kg6 7.Kd6 Bb6 8.Bd1 Ba7 9.Nc2 Nd3 10.Be2 Bb8+ (13.544.815) 6431
18/49 0:02 -1.26++ 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 e2 5.Bxe2 Nb4 6.Ne3 Kg6 7.Kd6 Bb6 8.Bd1 Ba7 9.Nc2 Nd3 (16.451.759) 6507
18/49 0:03 -1.28 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 Bc7 5.Nxe3 Bxg3 6.Nd5 Be5 7.Kc6 h5 8.Kb5 Nb8 (21.940.459) 6563
19/49 0:03 -1.28 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 Bc7 5.Nxe3 Bxg3 6.Kc6 Nb8+ 7.Kb6 Bf2 8.Nd5 Bd4 9.Kc7 Be5+ 10.Kb6 h5 (23.732.725) 6561
20/49 0:04 -1.32 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 Bc7 5.Nxe3 Bxg3 6.Kc6 Nb8+ 7.Kb6 Bf2 8.Nd5 Bd4 9.Kc7 Be5+ 10.Kb6 h5 (28.718.387) 6532
21/49 0:05 -1.28 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 Bc7 5.Nxe3 Bxg3 6.Kc6 Nb8+ 7.Kb6 Bf2 8.Nd5 Bd4 9.Kc7 Be5+ 10.Kb6 h5 (37.449.750) 6476
22/52 0:11 -1.47 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 Bc7 5.Nxe3 Bxg3 6.Kc6 Nb8+ 7.Kb6 Bf2 8.Nd5 Bd4 9.Kc7 Be5+ 10.Kb6 h5 (75.761.846) 6474
23/52 0:16 -1.47 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 Bc7 5.Nxe3 Bxg3 6.Kc6 Nb8+ 7.Kb6 Bf2 8.Nd5 Bd4 9.Kc7 Be5+ 10.Kb6 h5 (103.905.414) 6395
24/57 0:23 -1.47 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 Bc7 5.Nxe3 Bxg3 6.Kc6 Nb8+ 7.Kb6 Bf2 8.Nd5 Bd4 9.Kc7 Be5+ 10.Kb6 h5 (149.674.733) 6432
25/57 0:37 -1.39++ 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 Bc7 5.Nxe3 Bxg3 6.Kc6 Nb8+ 7.Kb6 Bf2 8.Nd5 Bd4 9.Kc7 Be5+ 10.Kb6 h5 (243.475.563) 6450
25/66 1:54 -1.89 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 Bc7 5.Nxe3 Bxg3 6.Kc6 Kg6 7.Kb6 Nc7 8.Bc2+ Kg5 9.Nd1 Be5 10.Nxc3 c4 (759.413.808) 6615
26/66 5:28 -1.99 1.d8Q Nf7+ 2.Ke7 Nxd8 3.Kxd8 Ba5+ 4.Kd7 Bc7 5.Nxe3 Bxg3 6.Kc6 Kg6 7.Kb6 Nc7 8.Bc2+ Kg5 9.Nd1 Be5 10.Nxc3 c4 (2.224.715.207) 6780
best move: d7-d8Q time: 5:29.172 min n/s: 6.780.000 CPU 99.6% n/s(1CPU): 6.807.228 nodes: 2.224.715.207

Engine: FireBird 1.2 x64 (4096 MB)
by Kranium and Sentinel, based on IppoLit

26.03 0:59 -2.00++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.035.487.264) 17362
26.03 0:59 -2.00++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.035.487.264) 17362
26.01 1:01 -1.92++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.067.539.069) 17283
26.01 1:01 -1.92++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.067.539.069) 17283
26.01 1:03 -1.80++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.094.957.952) 17196
26.01 1:03 -1.80++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.094.957.952) 17196
26.01 1:05 -1.62++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.127.742.599) 17111
26.01 1:05 -1.62++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.127.742.599) 17111
26.01 1:09 -1.35++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.179.340.041) 17049
26.01 1:09 -1.35++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.179.340.041) 17049
26.01 1:14 -0.95++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.275.390.055) 17151
26.01 1:14 -0.95++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.275.390.055) 17151
26.01 1:22 -0.35++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.435.272.155) 17334
26.01 1:22 -0.35++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Nf4+ Kf5 4.Bc2+ Kg4 5.Bd1+ Kf5 (1.435.272.155) 17334
26.01 1:33 +0.55++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Qe8 Kf3 6.Qh5+ Kf2 7.Qh2+ Ke1 8.Qh1+ Ke2 9.Qh2+ Ke1 (1.670.154.070) 17820
26.01 1:33 +0.55++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Qe8 Kf3 6.Qh5+ Kf2 7.Qh2+ Ke1 8.Qh1+ Ke2 9.Qh2+ Ke1 (1.670.154.070) 17820
26.01 1:52 +1.90++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Qe8 Kf3 6.Qh5+ Kxg3 7.Bd1 c2 8.Qg4+ Kf2 9.Qe2+ Kg3 (2.083.472.081) 18499
26.01 1:52 +1.90++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Qe8 Kf3 6.Qh5+ Kxg3 7.Bd1 c2 8.Qg4+ Kf2 9.Qe2+ Kg3 (2.083.472.081) 18499
26.01 2:59 +3.11 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Qe8 c4+ 6.Kc6 Ba3 7.Bd1+ Kh3 8.Qxe3 Nb4+ 9.Kb5 c2 10.g4+ (3.582.848.080) 19911
26.19 3:02 +3.11 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Qe8 c4+ 6.Kc6 Ba3 7.Bd1+ Kh3 8.Qxe3 Nb4+ 9.Kb5 c2 (3.627.829.212) 19849
27.01 3:30 +3.19++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Qe8 c4+ 6.Kc6 Ba3 7.Bd1+ Kh3 8.Qxe3 Nb4+ 9.Kb5 c2 (4.188.112.432) 19943
27.01 3:30 +3.19++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Qe8 c4+ 6.Kc6 Ba3 7.Bd1+ Kh3 8.Qxe3 Nb4+ 9.Kb5 c2 (4.188.112.432) 19943
27.01 3:43 +3.27++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Kc6 Nf3 6.Qg8+ Kh3 7.Qe6+ Kg2 8.Qxe3 Nd4+ 9.Kb7 (4.439.603.408) 19866
27.01 3:43 +3.27++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Kc6 Nf3 6.Qg8+ Kh3 7.Qe6+ Kg2 8.Qxe3 Nd4+ 9.Kb7 Nxc2 10.Qe4+ Kxg3 (4.439.603.408) 19866
27.01 4:03 +3.39++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Kc6 Nf3 6.Qg8+ Kh3 7.Qe6+ Kg2 8.Qxe3 Nd4+ 9.Kb7 Nxc(4.845.913.077) 19861
27.01 4:03 +3.39++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Kc6 Nf3 6.Qg8+ Kh3 7.Qe6+ Kg2 8.Qxe3 Nd4+ 9.Kb7 Nxc2 10.Qe4+ Kxg3 (4.845.913.077) 19861
27.01 4:23 +3.57++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Kc6 Nf3 6.Qg8+ Kh3 7.Qe6+ Kg2 8.Qxe3 Nd4+ 9.Kb7 Nxc2 10.Qe4+ Kxg3 (5.209.970.539) 19764
27.01 4:23 +3.57++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Kc6 Nf3 6.Qg8+ Kh3 7.Qe6+ Kg2 8.Qxe3 Nd4+ 9.Kb7 Nxc2 10.Qe4+ Kxg3 (5.209.970.539) 19764
27.01 4:53 +3.84++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Kc6 Ba3 6.Qd1+ Kh3 7.Qf1+ Kxg3 8.Qg1+ Kf4 9.Qh2+ Kf3 10.Bd1+ K(5.797.584.009) 19742
27.01 4:53 +3.84++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Kc6 Ba3 6.Qd1+ Kh3 7.Qf1+ Kxg3 8.Qg1+ Kf4 9.Qh2+ Kf3 10.Bd1+ Ke4 (5.797.584.009) 19742
27.01 5:48 +4.24++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Kc6 Ba3 6.Qd1+ Kh3 7.Qf1+ Kxg3 8.Qg1+ Kf3 9.Bd1+ Ke4 10.(6.980.566.609) 20026
27.01 5:48 +4.24++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Kc6 Ba3 6.Qd1+ Kh3 7.Qf1+ Kxg3 8.Qg1+ Kf3 9.Bd1+ Ke4 1(6.980.566.609) 20026
27.01 8:30 +4.84++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Kc6 Kf3 6.Bd1+ Kg2 7.Qd5+ Kh2 8.Qd3 c2 9.Bxc2 Nb8+ (10.588.865.508) 20753
27.01 8:30 +4.84++ 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Kc6 Kf3 6.Bd1+ Kg2 7.Qd5+ Kh2 8.Qd3 c2 9.Bxc2 Nb8+ (10.588.865.508) 20753
27.01 8:50 +4.84 1.Nf6+ Kg7 2.Nh5+ Kg6 3.Bc2+ Kxh5 4.d8Q Kg4 5.Kc6 Nf3 6.Qg8+ Kh3 7.Qe6+ Kg2 8.Qxe3 Nd4+ 9.Kb7 Nxc2 10.Qe4+ Kxg3 (10.963.948.529) 20657
best move: Ng4-f6 time: 8:51.859 min n/s: 20.657.000 CPU 77.9% n/s(1CPU): 26.517.329 nodes: 10.963.948.529

[Don]

[d] 8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - 0 1
White to play and win.

Fruit cannot see the winning move due to the horizon effect - how about your engine?

Komodo see's it in 6.3 seconds on a old core 2 duo with 32 meg hash. It wants to play Nf6 even earlier, but with a negative score and it changes its mind.


info depth 9 time 91 nodes 57346 score cp -313 nps 630175 pv g4f6 h7g7 f6h5 g7g6 h5f4 g6f5 d1c2 f5g4 c2d1 g4g3 f4e2 g3f2 e2c3
info depth 9 time 147 nodes 96288 score cp -235 nps 655020 pv d1c2 h7g7 g4e3 g5f7 d6e6 b4a5 e6d5 f7d8 d5c4 g7f6 e3d5 f6e6
info depth 9 time 265 nodes 207102 score cp -189 nps 781516 pv g4e3 b4a5 d1c2 h7g7 e3f5 g7g6 d6e7 a6b4 f5h4 g6g7
info depth 9 time 323 nodes 267894 score cp -189 nps 826833 pv g4e3 b4a5 d1c2 h7g7 e3f5 g7g6 d6e7 a6b4 f5h4 g6g7
info depth 10 time 388 nodes 335605 score cp -201 nps 864961 pv g4e3 b4a5 d1e2 a6b8 d6e7 h7g7 e3f5 g7g6 f5h4 g6h7 h4f5 b8c6
info depth 10 time 414 nodes 369381 score cp -201 nps 890074 pv g4e3 b4a5 d1e2 a6b8 d6e7 h7g7 e3f5 g7g6 f5h4 g6h7 h4f5 b8c6
info depth 11 time 479 nodes 444703 score cp -190 nps 928398 pv g4e3 b4a5 d1e2 a6b8 d6e7 b8c6 e7d6 c6d8 e2d3 h7g7 d6c5 g7f7
info depth 11 time 543 nodes 516424 score cp -190 nps 949308 pv g4e3 b4a5 d1e2 a6b8 d6e7 b8c6 e7d6 c6d8 e2d3 h7g7 d6c5 g7f7
info depth 12 time 729 nodes 751069 score cp -175 nps 1030272 pv g4e3 b4a5 d1e2 a6b8 d6e7 b8c6 e7d6 c6d8 e2d3 h7g7 d6c5 g7f7
info depth 12 time 812 nodes 839008 score cp -175 nps 1031990 pv g4e3 b4a5 d1e2 a6b8 d6e7 b8c6 e7d6 c6d8 e2d3 h7g7 d6c5 g7f7
info depth 13 time 1226 nodes 1378117 score cp -186 nps 1123159 pv g4e3 b4a5 d1e2 a6b8 d6e7 h7g7 e3f5 g7g6 f5h4 g6h7 e2d3 h7g8
info depth 13 time 1411 nodes 1600082 score cp -186 nps 1133202 pv g4e3 b4a5 d1e2 a6b8 d6e7 h7g7 e3f5 g7g6 f5h4 g6h7 e2d3 h7g8
info depth 14 time 2871 nodes 3595656 score cp -198 nps 1252405 pv g4e3 b4a5 d6c6 a5d8 d1c2 h7g7 c6b5 a6b8 e3f5 g7f6 b5c5 b8d7
info depth 14 time 3530 nodes 4448998 score cp -188 nps 1259982 pv d7d8q g5f7 d6e7 f7d8 e7d8 b4a5 d8d7 e3e2 d1e2 a6b4 g4e3 h7g6
info depth 14 time 3631 nodes 4563262 score cp -188 nps 1256750 pv d7d8q g5f7 d6e7 f7d8 e7d8 b4a5 d8d7 e3e2 d1e2 a6b4 g4e3 h7g6
info depth 15 time 3956 nodes 4987094 score cp -190 nps 1260640 pv d7d8q g5f7 d6e7 f7d8 e7d8 b4a5 d8d7 e3e2 d1e2 a6b4 g4e3 h7g6
info depth 15 time 6287 nodes 7911447 score cp 77 nps 1258181 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 g4f3 c2d1 f3f2
info depth 15 time 6329 nodes 7959992 score cp 77 nps 1257502 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 g4f3 c2d1 f3f2
info depth 16 time 8269 nodes 10324520 score cp 127 nps 1248430 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 g4f3 c2d1 f3f2
info depth 16 time 8322 nodes 10385444 score cp 127 nps 1247800 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 g4f3 c2d1 f3f2
info depth 17 time 9960 nodes 12372826 score cp 120 nps 1242126 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 17 time 10092 nodes 12533256 score cp 120 nps 1241777 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 18 time 15773 nodes 19662357 score cp 150 nps 1246504 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 18 time 15898 nodes 19811553 score cp 150 nps 1246087 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 19 time 23042 nodes 28551379 score cp 140 nps 1239101 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 g4f3 c2d1 f3f2
info depth 19 time 23338 nodes 28904898 score cp 140 nps 1238480 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 g4f3 c2d1 f3f2
info depth 20 time 45275 nodes 53779965 score cp 173 nps 1187851 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 20 time 46075 nodes 54632691 score cp 173 nps 1185708 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 21 time 71369 nodes 81841523 score cp 174 nps 1146721 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 21 time 72180 nodes 82661049 score cp 174 nps 1145191 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5

[Terry McCracken]

[d] 8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - 0 1
White to play and win.

Fruit cannot see the winning move due to the horizon effect - how about your engine?

Komodo see's it in 6.3 seconds on a old core 2 duo with 32 meg hash. It wants to play Nf6 even earlier, but with a negative score and it changes its mind.


info depth 9 time 91 nodes 57346 score cp -313 nps 630175 pv g4f6 h7g7 f6h5 g7g6 h5f4 g6f5 d1c2 f5g4 c2d1 g4g3 f4e2 g3f2 e2c3
info depth 9 time 147 nodes 96288 score cp -235 nps 655020 pv d1c2 h7g7 g4e3 g5f7 d6e6 b4a5 e6d5 f7d8 d5c4 g7f6 e3d5 f6e6
info depth 9 time 265 nodes 207102 score cp -189 nps 781516 pv g4e3 b4a5 d1c2 h7g7 e3f5 g7g6 d6e7 a6b4 f5h4 g6g7
info depth 9 time 323 nodes 267894 score cp -189 nps 826833 pv g4e3 b4a5 d1c2 h7g7 e3f5 g7g6 d6e7 a6b4 f5h4 g6g7
info depth 10 time 388 nodes 335605 score cp -201 nps 864961 pv g4e3 b4a5 d1e2 a6b8 d6e7 h7g7 e3f5 g7g6 f5h4 g6h7 h4f5 b8c6
info depth 10 time 414 nodes 369381 score cp -201 nps 890074 pv g4e3 b4a5 d1e2 a6b8 d6e7 h7g7 e3f5 g7g6 f5h4 g6h7 h4f5 b8c6
info depth 11 time 479 nodes 444703 score cp -190 nps 928398 pv g4e3 b4a5 d1e2 a6b8 d6e7 b8c6 e7d6 c6d8 e2d3 h7g7 d6c5 g7f7
info depth 11 time 543 nodes 516424 score cp -190 nps 949308 pv g4e3 b4a5 d1e2 a6b8 d6e7 b8c6 e7d6 c6d8 e2d3 h7g7 d6c5 g7f7
info depth 12 time 729 nodes 751069 score cp -175 nps 1030272 pv g4e3 b4a5 d1e2 a6b8 d6e7 b8c6 e7d6 c6d8 e2d3 h7g7 d6c5 g7f7
info depth 12 time 812 nodes 839008 score cp -175 nps 1031990 pv g4e3 b4a5 d1e2 a6b8 d6e7 b8c6 e7d6 c6d8 e2d3 h7g7 d6c5 g7f7
info depth 13 time 1226 nodes 1378117 score cp -186 nps 1123159 pv g4e3 b4a5 d1e2 a6b8 d6e7 h7g7 e3f5 g7g6 f5h4 g6h7 e2d3 h7g8
info depth 13 time 1411 nodes 1600082 score cp -186 nps 1133202 pv g4e3 b4a5 d1e2 a6b8 d6e7 h7g7 e3f5 g7g6 f5h4 g6h7 e2d3 h7g8
info depth 14 time 2871 nodes 3595656 score cp -198 nps 1252405 pv g4e3 b4a5 d6c6 a5d8 d1c2 h7g7 c6b5 a6b8 e3f5 g7f6 b5c5 b8d7
info depth 14 time 3530 nodes 4448998 score cp -188 nps 1259982 pv d7d8q g5f7 d6e7 f7d8 e7d8 b4a5 d8d7 e3e2 d1e2 a6b4 g4e3 h7g6
info depth 14 time 3631 nodes 4563262 score cp -188 nps 1256750 pv d7d8q g5f7 d6e7 f7d8 e7d8 b4a5 d8d7 e3e2 d1e2 a6b4 g4e3 h7g6
info depth 15 time 3956 nodes 4987094 score cp -190 nps 1260640 pv d7d8q g5f7 d6e7 f7d8 e7d8 b4a5 d8d7 e3e2 d1e2 a6b4 g4e3 h7g6
info depth 15 time 6287 nodes 7911447 score cp 77 nps 1258181 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 g4f3 c2d1 f3f2
info depth 15 time 6329 nodes 7959992 score cp 77 nps 1257502 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 g4f3 c2d1 f3f2
info depth 16 time 8269 nodes 10324520 score cp 127 nps 1248430 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 g4f3 c2d1 f3f2
info depth 16 time 8322 nodes 10385444 score cp 127 nps 1247800 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 g4f3 c2d1 f3f2
info depth 17 time 9960 nodes 12372826 score cp 120 nps 1242126 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 17 time 10092 nodes 12533256 score cp 120 nps 1241777 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 18 time 15773 nodes 19662357 score cp 150 nps 1246504 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 18 time 15898 nodes 19811553 score cp 150 nps 1246087 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 19 time 23042 nodes 28551379 score cp 140 nps 1239101 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 g4f3 c2d1 f3f2
info depth 19 time 23338 nodes 28904898 score cp 140 nps 1238480 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 g4f3 c2d1 f3f2
info depth 20 time 45275 nodes 53779965 score cp 173 nps 1187851 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 20 time 46075 nodes 54632691 score cp 173 nps 1185708 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 21 time 71369 nodes 81841523 score cp 174 nps 1146721 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5
info depth 21 time 72180 nodes 82661049 score cp 174 nps 1145191 pv g4f6 h7g7 f6h5 g7g6 d1c2 g6h5 d7d8q h5g4 d8e8 c5c4 d6c6 b4c5

Hi Don. I tried Rybka 3 on a Q6600 and Rybka hadn't a clue. Could you test it with Rybka 3 and 4?

[OliverUwira]

Hi Don. I tried Rybka 3 on a Q6600 and Rybka hadn't a clue. Could you test it with Rybka 3 and 4?

My Rybka 3 got it a depth 13. Stockfish 1.8 did only see it after it is shown 1.Nf6+. Same with my own engine.

May I say that this is a really sick mating line after 1.Nf6+ Kg6 2.Bc2+ Kh5 3.d8Q ... two black underpromotions to a knight to shove the mate beyond the horizon

[Dann Corbit]

Hi Don. I tried Rybka 3 on a Q6600 and Rybka hadn't a clue. Could you test it with Rybka 3 and 4?

My Rybka 3 got it a depth 13. Stockfish 1.8 did only see it after it is shown 1.Nf6+. Same with my own engine.

May I say that this is a really sick mating line after 1.Nf6+ Kg6 2.Bc2+ Kh5 3.d8Q ... two black underpromotions to a knight to shove the mate beyond the horizon

If it needs underpromotions, Rybka might have a problem. It has some difficulty with underpromotions, but I don't remember exactly what.

[OliverUwira]

Hi Don. I tried Rybka 3 on a Q6600 and Rybka hadn't a clue. Could you test it with Rybka 3 and 4?

My Rybka 3 got it a depth 13. Stockfish 1.8 did only see it after it is shown 1.Nf6+. Same with my own engine.

May I say that this is a really sick mating line after 1.Nf6+ Kg6 2.Bc2+ Kh5 3.d8Q ... two black underpromotions to a knight to shove the mate beyond the horizon

If it needs underpromotions, Rybka might have a problem. It has some difficulty with underpromotions, but I don't remember exactly what.

Strange, I just checked again and now Rybka 3 doesn't find it any more. It now fails high on its mainline 1.d8Q at depth 14 with 1.Nf6+, researches, and switches back to 1.d8Q.

The interesting thing about the underpromotions here is that they are not required to give mate but to prevent it. So we have:

Code: Select all

1. Nf6+ Kg7 2. Nh5+ Kg6 3. Bc2+ Kxh5 4. d8=Q Nf7+ 5. Ke6 Nxd8+ 6. Kf5 e2 7. Be4 e1=N 8. Bd5 c2 9. Bc4 c1=N 10. Bb5 Nc6 11. Bxc6 Nc7 12. Ba4 Ne2 13. Bd1 Nf3 14. Bxe2 Bd2 15. Bxf3#

Without the underpromotions at moves 7 and 9, the mate would be found more easily, because the underpromotions happen to protect the squares where the white bishop is about to give mate.

After each underpromotion, a quiet move is required to threaten mate from another square. Neither the underpromotions nor the quiet moves usually trigger extensions and they're not considered in the quiescence search. Thus the mate is delayed long enough to fall beyond the horizon, which must be 30 ply deep to have a chance of discovering the mate.

An engine with indiscriminate check extensions should perform better here.

[Don]

Hi Don. I tried Rybka 3 on a Q6600 and Rybka hadn't a clue. Could you test it with Rybka 3 and 4?

My Rybka 3 got it a depth 13. Stockfish 1.8 did only see it after it is shown 1.Nf6+. Same with my own engine.

May I say that this is a really sick mating line after 1.Nf6+ Kg6 2.Bc2+ Kh5 3.d8Q ... two black underpromotions to a knight to shove the mate beyond the horizon

If it needs underpromotions, Rybka might have a problem. It has some difficulty with underpromotions, but I don't remember exactly what.

The version of Komodo that I am using does knight check under-promotions. I have not studied this problem to understand what is going on.

[gerold]

Rybka v 2.2 found it in 1 sec.