Challenge

Discussion of chess software programming and technical issues.

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Kempelen
Posts: 620
Joined: Fri Feb 08, 2008 10:44 am
Location: Madrid - Spain

Challenge

Post by Kempelen »

This problem is mate in 6!!!.

Image
FEN: n1N3br/2p1Bpkr/1pP2R1b/pP1p1PpR/Pp4P1/1P6/1K1P4/8 w - - 0

I have not found any engine that can solve it. I thought strong engines would fine the mate in a few seconds. Craft need more than two minutes in my machine to find a very looooong sequence for mate, but the mate in 6 is hidden to it.

why?
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smrf
Posts: 484
Joined: Mon Mar 13, 2006 11:08 am
Location: Klein-Gerau, Germany

Re: Challenge

Post by smrf »

SMIRF MS-174d-0 calculates:

Code: Select all

00:01.1 (08.01=) +M~006 1.Rh1 (Kc1) d4 2.Ra1 d3 3.Ra3 bxa3+ 4.Ka1 a2 5.Ba3 Kxf6 6.Bb2#
00:00.9 (08.01+) +3.742 1.Rh1 (Kc1) d4 2.Re1 d3 3.Nd6 cxd6 4.Rxd6 f6 5.Bxf6+ Kf8 6.Rd8+ Kf7 7.Bxh8 Rxh8 8.Rxa8 Kg7
00:00.6 (07.04=) +3.299 1.Rh1 (Kc1) d4 2.Re1 d3 3.Nd6 cxd6 4.Rxd6 f6 5.Bxf6+ Kf8 6.Rd8+ Kf7 7.Bxh8 Rxh8 8.Rxa8 Kg7
00:00.5 (07.02=) +1.297 1.Kc1 (Rh3) d4 2.Rh3 d3 3.Bd8 Kf8 4.Rxd3 Kg7 5.Re3 Kf8 6.Be7+ Ke8
00:00.3 (07.01+) +1.295 1.Rh3 (Kc1) d4 2.Kc1 d3 3.Bd8 Kf8 4.Rxd3 Kg7 5.Re3 Kf8 6.Be7+ Ke8
00:00.2 (06.02=) +1.074 1.Rh3 (Kc1) d4 2.Kc1 d3 3.Bd8 Kf8 4.Rxd3 Kg7 5.Re3 Kf8 6.Be7+ Ke8
00:00.2 (06.02+) +1.076 1.Kc1 (Rh3) d4 2.Rh3 d3 3.Bd8 Kf8 4.Rxd3 Kg7 5.Re3 Kf8 6.Be7+ Ke8
00:00.0 (05.02=) +0.271 1.Rh3 (Kc1) d4 2.Kc1 d3 3.Bd8 Kf8 4.Be7+ Kg7 5.Bd8 Kf8 6.Be7+ Kg7 7.Bd8 Kf8 8.Be7+ Kg7
00:00.0 (02.13=) +0.020 1.Kc1 (d4) d4 2.Bf8+
P.S.: several Zugzwang situations included.
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dlunow

Re: Challenge

Post by dlunow »

The problem is the null move pruning. Without null move verification the mate in 6 is never solved.

Code: Select all

Analysis by Fritz 11 (Nullmove pruning disabled):

1.Nc8-d6 c7xd6 2.Rf6xd6 Na8-c7 3.Be7-f6+ Kg7-f8 4.Bf6xh8 Rh7xh8 5.Rh5xh6 Rh8xh6 
  +-  (1.45)   Depth: 9/17   00:00:00  20kN
1.Nc8-d6 c7xd6 2.Rf6xd6 Na8-c7 3.Be7-f6+ Kg7-f8 4.Bf6xh8 Rh7xh8 5.Rh5xh6 Rh8xh6 6.Rd6xh6 Kf8-e7 
  +/-  (1.14)   Depth: 10/21   00:00:00  58kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rd6xh6 Rh8xh6 6.Rh5xh6 Na8-c7 7.Rh6-h1 
  +-  (2.57)   Depth: 11/22   00:00:00  170kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rd6xh6 Rh8xh6 6.Rh5xh6 Na8-c7 7.Rh6-g6 d5-d4 8.Rg6xg5 
  +-  (3.38)   Depth: 12/25   00:00:00  403kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rd6xh6 Rh8xh6 6.Rh5xh6 Na8-c7 7.Rh6-g6 d5-d4 8.Rg6xg5 
  +-  (3.38)   Depth: 13/25   00:00:00  1000kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rd6xh6 Rh8xh6 6.Rh5xh6 Kf7-e7 7.Rh6-g6 Bg8-f7 8.Rg6xg5 Na8-c7 
  +-  (3.15)   Depth: 14/29   00:00:01  2447kN
1.Rh5-h1 d5-d4 2.Rh1-a1 d4-d3 3.Ra1-a3 b4xa3+ 4.Kb2-a1 a3-a2 5.Be7-a3 Kg7xf6 6.Ba3-b2# 
  +-  (#6)   Depth: 14/29   00:00:01  2961kN
1.Rh5-h1 d5-d4 2.Rh1-a1 d4-d3 3.Ra1-a3 b4xa3+ 4.Kb2-a1 a3-a2 5.Be7-a3 Kg7xf6 6.Ba3-b2# 
  +-  (#6)   Depth: 14/31   00:00:02  4955kN

Code: Select all

Analysis by Fritz 11 (Nullmove pruning enabled):

1.Nc8-d6 c7xd6 2.Rf6xd6 Na8-c7 3.Be7-f6+ Kg7-f8 4.Bf6xh8 Rh7xh8 5.Rh5xh6 Rh8xh6 
  +-  (1.45)   Depth: 9/16   00:00:00  7kN
1.Nc8-d6 c7xd6 2.Rf6xd6 Na8-c7 3.Be7-f6+ Kg7-f8 4.Bf6xh8 Rh7xh8 5.Rh5xh6 Rh8xh6 6.Rd6xh6 Kf8-e7 
  +/-  (1.14)   Depth: 10/21   00:00:00  12kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rd6xh6 Rh8xh6 6.Rh5xh6 Na8-c7 7.Rh6-h1 
  +-  (2.57)   Depth: 11/21   00:00:00  32kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rd6xh6 Rh8xh6 6.Rh5xh6 Na8-c7 7.Rh6-g6 d5-d4 8.Rg6xg5 
  +-  (3.38)   Depth: 12/22   00:00:00  49kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rd6xh6 Rh8xh6 6.Rh5xh6 Na8-c7 7.Rh6-g6 d5-d4 8.Rg6xg5 
  +-  (3.38)   Depth: 13/25   00:00:00  82kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rd6xh6 Rh8xh6 6.Rh5xh6 Kf7-e7 7.Rh6-g6 Bg8-f7 8.Rg6xg5 Na8-c7 
  +-  (3.15)   Depth: 14/28   00:00:00  154kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rd6xh6 Rh8xh6 6.Rh5xh6 Kf7-e7 7.Rh6-h8 Ke7-f7 8.Kb2-c2 Na8-c7 9.Kc2-d3 
  +-  (2.82)   Depth: 15/27   00:00:00  286kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rd6xh6 Rh8xh6 6.Rh5xh6 Kf7-e7 7.Rh6-h8 Ke7-f7 8.Kb2-c2 Kf7-g7 9.Rh8-h1 Kg7-f6 
  +-  (2.96)   Depth: 16/26   00:00:00  523kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rd6xh6 Rh8xh6 6.Rh5xh6 Kf7-e7 7.Kb2-c2 Bg8-f7 8.Rh6-h8 Na8-c7 9.Rh8-b8 Ke7-d6 10.Rb8xb6 
  +-  (2.97)   Depth: 17/28   00:00:00  905kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rd6xh6 Rh8xh6 6.Rh5xh6 Kf7-e7 7.Kb2-c2 Bg8-f7 8.Rh6-h8 Na8-c7 9.Rh8-b8 d5-d4 10.Rb8xb6 Ke7-d6 
  +-  (2.95)   Depth: 18/31   00:00:01  1985kN
1.Kb2-c2 d5-d4 2.Nc8-d6 c7xd6 3.Rf6xd6 f7-f6 4.Be7xf6+ Kg7-f8 5.Bf6xh8 Rh7xh8 6.Rd6xh6 Rh8xh6 7.Rh5xh6 d4-d3+ 8.Kc2-b2 Na8-c7 9.Rh6-d6 Kf8-e8 10.Rd6-g6 Bg8-d5 11.Rg6xg5 
  +-  (3.17)   Depth: 18/35   00:00:01  3270kN
1.Kb2-c2 d5-d4 2.Nc8-d6 c7xd6 3.Rf6xd6 f7-f6 4.Be7xf6+ Kg7-f8 5.Bf6xh8 Rh7xh8 6.Rd6xh6 Rh8xh6 7.Rh5xh6 d4-d3+ 8.Kc2-b2 Kf8-e7 9.Rh6-h8 Ke7-f7 10.Rh8-h3 Na8-c7 11.Rh3xd3 Kf7-f6 12.Rd3-d7 
  +-  (3.10)   Depth: 19/32   00:00:02  4380kN
1.Kb2-c2 d5-d4 2.Nc8-d6 c7xd6 3.Rf6xd6 f7-f6 4.Be7xf6+ Kg7-f8 5.Bf6xh8 Rh7xh8 6.Rd6xh6 Rh8xh6 7.Rh5xh6 d4-d3+ 8.Kc2-b2 Kf8-e7 9.Rh6-h8 Ke7-f7 10.Rh8-h3 Na8-c7 11.Rh3xd3 Kf7-f6 12.Rd3-d7 
  +-  (3.10)   Depth: 20/35   00:00:04  7196kN
1.Kb2-c2 d5-d4 2.Nc8-d6 c7xd6 3.Rf6xd6 f7-f6 4.Be7xf6+ Kg7-f7 5.Bf6xh8 Rh7xh8 6.Rd6xh6 Rh8xh6 7.Rh5xh6 Kf7-e7 8.f5-f6+ Ke7-f8 9.Kc2-d3 Bg8xb3 10.Rh6-h8+ Bb3-g8 11.Kd3xd4 Na8-c7 12.Kd4-e5 Kf8-f7 13.d2-d4 
  +-  (2.94)   Depth: 21/38   00:00:08  13473kN

Code: Select all

Analysis by Fruit 2.1: (null move verification: ever)

1.d2-d4 
  =  (0.00)   Depth: 3/10   00:00:00
1.d2-d4 
  =  (0.00)   Depth: 3/10   00:00:00
1.d2-d4 
  =  (0.00)   Depth: 3/10   00:00:00
1.d2-d4 
  =  (0.00)   Depth: 3/10   00:00:00
1.d2-d4 
  =  (0.00)   Depth: 3/10   00:00:00
1.d2-d4 
  =  (0.00)   Depth: 3/11   00:00:00
1.d2-d4 
  =  (0.00)   Depth: 3/11   00:00:00
1.d2-d4 
  =  (0.00)   Depth: 3/11   00:00:00
1.d2-d4 
  =  (0.00)   Depth: 4/11   00:00:00
1.Nc8-d6 c7xd6 2.Rf6xd6 Na8-c7 3.Be7-f6+ Kg7-f8 4.Bf6xh8 
  +/-  (0.71)   Depth: 4/12   00:00:00
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 
  +-  (2.31)   Depth: 5/17   00:00:00
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Bh6-g7+ 5.Bh8xg7 Rh7xh5 6.g4xh5 Kf7xg7 
  +-  (2.82)   Depth: 6/17   00:00:00  19kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Bh6-f8 5.Rh5xh7+ Bg8xh7 6.Rd6xd5 
  +-  (2.99)   Depth: 7/18   00:00:00  23kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Bh6-f8 5.c6-c7 Na8xc7 6.Rd6-d7+ Bf8-e7 7.Rd7xc7 Rh7xh5 8.g4xh5 
  +-  (3.04)   Depth: 8/21   00:00:00  47kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rh5xh6 Rh8xh6 6.Rd6xh6 Na8-c7 7.Kb2-c2 
  +-  (2.77)   Depth: 9/23   00:00:00  96kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rh5xh6 Rh8xh6 6.Rd6xh6 Na8-c7 7.Rh6-g6 Bg8-h7 8.Rg6xg5 
  +-  (3.08)   Depth: 10/28   00:00:00  186kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rh5xh6 Rh8xh6 6.Rd6xh6 Na8-c7 7.Rh6-g6 Bg8-h7 8.Rg6xg5 
  +-  (3.08)   Depth: 11/30   00:00:00  350kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rh5xh6 Rh8xh6 6.Rd6xh6 Kf7-e7 7.f5-f6+ Ke7-f7 8.Kb2-c2 Na8-c7 9.Kc2-d3 
  +-  (2.89)   Depth: 12/34   00:00:00  756kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rh5xh6 Rh8xh6 6.Rd6xh6 Kf7-e7 7.Rh6-h8 Ke7-f7 8.Rh8-h5 Kf7-f6 9.Rh5-h1 
  +-  (2.91)   Depth: 13/40   00:00:01  1684kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rh5xh6 Rh8xh6 6.Rd6xh6 Kf7-e7 7.d2-d4 Na8-c7 8.Rh6-g6 Bg8-f7 9.Rg6xg5 Ke7-f6 
  +-  (2.80)   Depth: 14/40   00:00:04  4415kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rh5xh6 Rh8xh6 6.Rd6xh6 Kf7-e7 7.Rh6-h8 Ke7-f7 8.Kb2-c2 Na8-c7 9.Kc2-d3 Kf7-g7 10.Rh8-h1 
  +-  (2.97)   Depth: 15/42   00:00:09  9471kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rh5xh6 Rh8xh6 6.Rd6xh6 Kf7-e7 7.Rh6-h8 Ke7-f7 8.Kb2-c2 Na8-c7 9.Rh8-h6 Kf7-e7 10.f5-f6+ Ke7-e6 11.Kc2-d3 
  +-  (2.75)   Depth: 16/42   00:00:18  17970kN
1.d2-d3 d5-d4 2.Nc8-d6 c7xd6 3.Rf6xd6 f7-f6 4.Be7xf6+ Kg7-f7 5.Bf6xh8 Rh7xh8 6.Rh5xh6 Rh8xh6 7.Rd6xh6 Kf7-e8 8.f5-f6 Na8-c7 9.Rh6-g6 Bg8-e6 10.Rg6xg5 Nc7-d5 
  +-  (2.90)   Depth: 16/52   00:00:33  31666kN
1.d2-d3 d5-d4 2.Nc8-d6 c7xd6 3.Rf6xd6 f7-f6 4.Be7xf6+ Kg7-f7 5.Bf6xh8 Rh7xh8 6.Rh5xh6 Rh8xh6 7.Rd6xh6 Kf7-e7 8.Rh6-h8 Ke7-f7 9.Rh8-h1 Na8-c7 10.Rh1-e1 Kf7-f6 11.Kb2-c2 
  +-  (2.37)   Depth: 17/52   00:00:43  41520kN
1.Nc8-d6 c7xd6 2.Rf6xd6 f7-f6 3.Be7xf6+ Kg7-f7 4.Bf6xh8 Rh7xh8 5.Rh5xh6 Rh8xh6 6.Rd6xh6 Kf7-e7 7.Rh6-h2 Na8-c7 8.Rh2-h8 Ke7-f7 9.Rh8-h6 Kf7-e7 10.Rh6-g6 Bg8-f7 11.Rg6xg5 
  +-  (2.73)   Depth: 17/52   00:00:53  50887kN
1.Rh5-h1 d5-d4 2.Nc8-d6 c7xd6 3.Rf6xd6 f7-f6 4.Be7xf6+ Kg7-f7 5.Bf6xd4 Na8-c7 6.Rd6-d7+ Kf7-f8 7.Bd4xh8 Rh7xh8 8.Rd7xc7 Bg8-f7 9.f5-f6 Bf7-e6 10.Rc7-a7 Be6-c8 11.Rh1-g1 
  +-  (3.95)   Depth: 17/54   00:00:58  55900kN
1.Rh5-h1 d5-d4 2.Nc8-d6 c7xd6 3.Rf6xd6 f7-f6 4.Be7xf6+ Kg7-f7 5.Bf6xd4 Na8-c7 6.Rd6-d7+ Kf7-e8 7.Bd4xh8 Rh7xh8 8.Rd7xc7 Ke8-f8 9.f5-f6 Bg8-e6 10.Rc7-a7 Be6-c8 11.Rh1-e1 Rh8-g8 
  +-  (4.49)   Depth: 18/62   00:01:14  71888kN
1.Rh5-h1 d5-d4 2.Nc8-d6 c7xd6 3.Rf6xd6 f7-f6 4.Be7xf6+ Kg7-f7 5.Bf6xd4 Na8-c7 6.Rd6-d7+ Kf7-f8 7.Bd4xh8 Bh6-g7+ 8.Bh8xg7+ Rh7xg7 9.Rh1-e1 Rg7-f7 10.f5-f6 Rf7xf6 11.Rd7xc7 Rf6-f3 12.Rc7-c8+ Kf8-g7 13.Re1-e7+ Bg8-f7 14.Re7-e3 
  +-  (4.77)   Depth: 19/66   00:01:54  113mN
1.Rh5-h1 d5-d4 2.Rh1-a1 d4-d3 3.Ra1-a3 b4xa3+ 4.Kb2-a1 a3-a2 5.Be7-a3 Kg7xf6 6.Ba3-b2# 
  +-  (#6)   Depth: 20/66   00:03:02  186mN
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User avatar
hgm
Posts: 28355
Joined: Fri Mar 10, 2006 10:06 am
Location: Amsterdam
Full name: H G Muller

Re: Challenge

Post by hgm »

But once it has found it, would it acually play the moves... :wink:
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User avatar
smrf
Posts: 484
Joined: Mon Mar 13, 2006 11:08 am
Location: Klein-Gerau, Germany

Re: Challenge

Post by smrf »

hgm wrote:But once it has found it, would it acually play the moves... :wink:
No problem for SMIRF MS-174d-0 (donators' bonus version) :D :

Code: Select all

[Event ""]
[Site ""]
[Date "2008.06.20"]
[Time "17:52:09"]
[Round ""]
[White "White"]
[Black "Black"]
[Result "1-0"]
[SetUp "1"]
[FEN "n1N3br/2p1Bpkr/1pP2R1b/pP1p1PpR/Pp4P1/1P6/1K1P4/8 w - - 0 1"]

1. Rh1 {(08.01=) +M~006} d4 {(02.00?) no choice} 2. Ra1 {(04.02=) +M~005} d3
{(03.00?) no choice} 3. Ra3 {(03.01=) +M~004} bxa3+ {(02.00?) no choice} 4. Ka1
{(02.01=) +M~003} a2 {(02.00?) no choice} 5. Ba3 {(02.01=) +M~002} Kxf6
{(02.00?) no choice} 6. Bb2# {(02.00?) +M~001} 1-0
(Don't know if also, when communicating by Smirf-o-Glot.)
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User avatar
michiguel
Posts: 6401
Joined: Thu Mar 09, 2006 8:30 pm
Location: Chicago, Illinois, USA

Re: Challenge

Post by michiguel »

Kempelen wrote:This problem is mate in 6!!!.

Image
FEN: n1N3br/2p1Bpkr/1pP2R1b/pP1p1PpR/Pp4P1/1P6/1K1P4/8 w - - 0

I have not found any engine that can solve it. I thought strong engines would fine the mate in a few seconds. Craft need more than two minutes in my machine to find a very looooong sequence for mate, but the mate in 6 is hidden to it.

why?
Gaviota finds it in a minute and a half in an Intel ~2 GHz.

The score (32089) correspond to mate in 11 plies (32100-32089), which is mate in 6. It does not show the PV because it fails high and with the mate score at 12 plies it realizes there is nothing better and wants to play the move. When I follow the moves, Gaviota really sees it. I do not like this output and I will change it.

Code: Select all

    198464   7:      0.6    +1.18  1.Nd6 cxd6 2.Rxd6 f6 3.Bxf6+ Kf7 4.Bxh8
                                   Bg7+ 5.Bxg7 Rxh5 6.gxh5 Kxg7
    199428   8       0.6      :-)  1.Nd6
    243626   8       0.7    +1.87  1.Nd6 cxd6 2.Rxd6 f6 3.Bxf6+ Kf8 4.Bxh8
                                   Rxh8 5.Rhxh6 Rxh6 6.Rxh6
    497593   8:      1.4    +1.87  1.Nd6 cxd6 2.Rxd6 f6 3.Bxf6+ Kf8 4.Bxh8
                                   Rxh8 5.Rhxh6 Rxh6 6.Rxh6
    624823   9       1.8    +1.82  1.Nd6 cxd6 2.Rxd6 f6 3.Bxf6+ Kf8 4.Bxh8
                                   Rxh8 5.Rf6+ Ke7 6.Rhxh6 Rxh6 7.Rxh6
   1432754   9:      4.0    +1.82  1.Nd6 cxd6 2.Rxd6 f6 3.Bxf6+ Kf8 4.Bxh8
                                   Rxh8 5.Rf6+ Ke7 6.Rhxh6 Rxh6 7.Rxh6
   1690039  10       4.8    +1.82  1.Nd6 cxd6 2.Rxd6 f6 3.Bxf6+ Kf8 4.Bxh8
                                   Rxh8 5.Rhxh6 Rxh6 6.Rxh6 d4 7.Rg6
   3918158  10:     10.9    +1.82  1.Nd6 cxd6 2.Rxd6 f6 3.Bxf6+ Kf8 4.Bxh8
                                   Rxh8 5.Rhxh6 Rxh6 6.Rxh6 d4 7.Rg6
   4451256  11      12.4    +1.95  1.Nd6 cxd6 2.Rxd6 f6 3.Bxf6+ Kf8 4.Bxh8
                                   Rxh8 5.Rhxh6 Rxh6 6.Rxh6 Bf7 7.Rh8+ Bg8
                                   8.Kc2
  11359050  11:     31.3    +1.95  1.Nd6 cxd6 2.Rxd6 f6 3.Bxf6+ Kf8 4.Bxh8
                                   Rxh8 5.Rhxh6 Rxh6 6.Rxh6 Bf7 7.Rh8+ Bg8
                                   8.Kc2
  11392329  12      31.4      :-)  1.Nd6
  14906030  12      41.8    +2.62  1.Nd6 cxd6 2.Rxd6 f6 3.Bxf6+ Kf8 4.Bxh8
                                   Rxh8 5.Rhxh6 Rxh6 6.Rxh6 Nc7 7.Rg6 Ne8
                                   8.Rxg5
  35236715  12      97.1      :-)  1.Rh1

Ply: 12
Rh5-h1
Score: 125.35 (32089)  Evals: 22078197   Time: 97.1s   nps: 363044  Q/all: 0.02
           nodes      cutoffs       missed     tree_exp
path    34535916      3697599       192714         1.05
quies     700799       296283        27729         1.09
all     35236715      3993882       220443         1.06
hashtable=  attempts: 34456993   hits: 43.6%   perfect: 24.8%
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User avatar
abik
Posts: 823
Joined: Fri Dec 01, 2006 10:46 pm
Location: Mountain View, CA, USA
Full name: Aart Bik

Re: Challenge

Post by abik »

He, finally something Bikjump does not do so badly :-)
info depth 1 seldepth 11 nodes 179 tbhits 0 time 0 score cp -402 pv f6h6
info depth 1 seldepth 11 nodes 758 tbhits 0 time 0 score cp -253 pv c8a7
info depth 1 seldepth 11 nodes 917 tbhits 0 time 0 score cp 0 pv d2d4
info depth 2 seldepth 2 nodes 924 tbhits 0 time 0 score cp 0 pv d2d4
info depth 3 seldepth 3 nodes 5129 tbhits 0 time 0 score cp 0 pv d2d4
info depth 4 seldepth 4 nodes 8891 tbhits 0 time 10 score cp 0 pv d2d4
info depth 5 seldepth 5 nodes 62696 tbhits 0 time 60 score cp 0 pv d2d4
info depth 6 seldepth 6 nodes 77408 tbhits 0 time 80 score cp 0 pv d2d4
info depth 6 seldepth 23 nodes 107796 tbhits 0 time 110 score cp 189 pv d2d3 d5d4 c8d6 c7d6 f6d6 f7f6 e7f6 g7f8 f6h8 h7h8
info depth 7 seldepth 17 nodes 334031 tbhits 0 time 310 score cp 189 pv d2d3 d5d4 c8d6
info depth 8 seldepth 27 nodes 465633 tbhits 0 time 440 score cp 189 pv d2d3 d5d4 c8d6 c7d6 f6d6 f7f6 e7f6 g7f8 f6h8 h7h8 h5h6 h8h6
info depth 8 seldepth 29 nodes 745629 tbhits 0 time 700 score cp 205 pv b2c1 d5d4 c8d6 c7d6 f6d6 f7f6 e7f6 g7f8 d6d8 f8f7 f6h8 d4d3
info depth 8 seldepth 29 nodes 1231967 tbhits 0 time 1120 score mate 6 pv h5h1 d5d4 h1a1 d4d3 a1a3 b4a3 b2a1 a3a2 e7a3 g7f6 a3b2
bestmove h5h1 ponder d5d4
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User avatar
hgm
Posts: 28355
Joined: Fri Mar 10, 2006 10:06 am
Location: Amsterdam
Full name: H G Muller

Re: Challenge

Post by hgm »

The important question, of course, is if the ability to find the solution to this problem makes the engine stronger or weaker.

Any opinions on that?

My conjecture is that being able to find the mate here is an indication that the engine wastes too much time on searching unlikely lines, and thus is unneccesary weak. :roll:
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User avatar
abik
Posts: 823
Joined: Fri Dec 01, 2006 10:46 pm
Location: Mountain View, CA, USA
Full name: Aart Bik

Re: Challenge

Post by abik »

My conjecture is that being able to find the mate here is an indication that the engine wastes too much time on searching unlikely lines, and thus is unneccesary weak.
Yes, your subtle point is well-taken.

I actually implemented these tactical extensions on purpose (based on a few interesting deep mate tests) to give the engine at least some edge in those problems. But my overall rating could give some validation to your conjecture :oops:
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Harald Johnsen

Re: Challenge

Post by Harald Johnsen »

But zugzwang is a real problem, I'm wondering how many middle or endgame positions are wasted by the stupid null move search.

How to solve this easy problem ?

[d] 8/6B1/p5p1/Pp4kp/1P5r/5P1Q/4q1PK/8 w - - 0 32 bm Qxh4

[d] 8/8/p7/Pp2B1pp/1P5k/5P2/5qPK/8 b - - 3 35

This is the position where black save it's queen by null moving.

HJ.
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