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Subject: Re: Another interesting Anti-Null move position (from a real game)

Author: Jaime Benito de Valle Ruiz

Date: 15:35:11 06/14/04

Go up one level in this thread


On June 14, 2004 at 18:30:07, Omid David Tabibi wrote:

>On June 14, 2004 at 18:22:12, Jaime Benito de Valle Ruiz wrote:
>
>>>1.gxh5 Qg4+ 2.Kf2 Qf4+ 3.Ke1 Kxh5 4.Ke2 g5 5.Kd3 Qf1+ 6.Kd2
>>>  ³  (-0.30)   Depth: 8/28   00:00:01  558kN
>>>1.gxh5 Qg4+ 2.Kf2 Qf4+ 3.Ke2 gxh5 4.Qg7+ Kh4 5.Qd4 Qg4+ 6.Kd2 Qe6 7.Qd5
>>>  ³  (-0.30)   Depth: 9/31   00:00:02  1287kN
>>>1.Qd2+
>>>  ³  (-0.29)   Depth: 9/31   00:00:02  1450kN
>>>1.Qd2+
>>>  =  (0.00)   Depth: 9/31   00:00:02  1451kN
>>>1.Qd2+
>>>  ²  (0.60)   Depth: 9/31   00:00:02  1452kN
>>>1.Qd2+ Kxg4 2.Qe3 b5 3.axb5 a4 4.bxa4
>>>  ±  (0.79)   Depth: 9/31   00:00:02  1454kN
>>>1.Qd2+ Kxg4 2.Qe3 b5 3.axb5 a4 4.bxa4
>>>  ±  (0.79)   Depth: 10/31   00:00:03  1533kN
>>>1.Qd2+
>>>  ±  (1.09)   Depth: 11/31   00:00:03  1721kN
>>>1.Qd2+
>>>  +-  (1.69)   Depth: 11/31   00:00:04  1726kN
>>>1.Qd2+ Kxg4 2.Qe3 b5 3.axb5 a4 4.bxa4 b3 5.Qxb3
>>>  +-  (2.65)   Depth: 11/32   00:00:04  1836kN
>>>1.Qd2+
>>>  +-  (2.35)   Depth: 12/34   00:00:05  2428kN
>>>1.Qd2+
>>>  +-  (1.75)   Depth: 12/34   00:00:05  2939kN
>>>1.Qd2+ Kxg4 2.Qe3 b5 3.axb5 a4 4.bxa4 b3 5.Qxb3
>>>  +-  (2.65)   Depth: 12/34   00:00:05  2965kN
>>>1.Qd2+
>>>  +-  (2.35)   Depth: 13/36   00:00:07  4004kN
>>>1.Qd2+
>>>  +-  (1.75)   Depth: 13/36   00:00:07  4759kN
>>>1.Qd2+ Kxg4 2.Qe3 b5 3.axb5 a4 4.bxa4 b3 5.Qxb3 Kf4 6.Qf3+ Ke5 7.Qg3+ Qxg3+
>>>8.Kxg3
>>>  +-  (2.51)   Depth: 13/36   00:00:07  4839kN, tb=2
>>>1.Qd2+
>>>  +-  (2.21)   Depth: 14/41   00:00:10  7208kN, tb=2
>>>1.Qd2+
>>>  +-  (2.81)   Depth: 14/41   00:00:11  7429kN, tb=9
>>>1.Qd2+ Kxg4 2.Qe3 b5 3.axb5 a4 4.bxa4 b3 5.Qxb3 Kf4 6.Qf7+ Ke5 7.Qxg6
>>>  +-  (3.16)   Depth: 14/41   00:00:11  7568kN, tb=9
>>>1.Qd2+
>>>  +-  (3.46)   Depth: 15/41   00:00:15  10115kN, tb=14
>>>1.Qd2+
>>>  +-  (4.06)   Depth: 15/41   00:00:15  10477kN, tb=14
>>>1.Qd2+
>>>  +-  (5.86)   Depth: 15/45   00:00:16  11180kN, tb=14
>>>1.Qd2+ Kxg4 2.Qe3 b5 3.axb5 a4 4.b6 axb3 5.b7 b2 6.b8Q Qh1+ 7.Kxh1 b1Q+ 8.Kg2
>>>Qb2+ 9.Kf1 Qa1+ 10.Kf2 Qf6+ 11.Ke2
>>>  +-  (11.75)   Depth: 15/47   00:00:18  12776kN, tb=14
>>>
>>>
>>>If I disable verfied null-move pruning, Falcon doesn't find the correct move.
>>
>>Interesting... My engine (Ayito) definitely finds it very fast without
>>null-move, and Falcon is far far better than Ayito. Engines such as Ruffian or
>>Crafty (to name two) stick to gxh5 at depth 14, and don't find it after over 1
>>minute.
>>
>>
>>>I use verified null-move pruning (an improved version of it).
>>
>>Maybe this is why your engine finds it.
>
>Yes. The following is the analysis with verified null-move disabled:
>
>1.gxh5 Qg4+ 2.Kf2 Qf4+ 3.Ke1 Kxh5 4.Ke2 g5 5.Kd3 Qf1+ 6.Kd2
>  ³  (-0.30)   Depth: 8/28   00:00:00  556kN
>1.gxh5 Qg4+ 2.Kf2 Qf4+ 3.Ke2 gxh5 4.Qg7+ Kh4 5.Qd4 Qg4+ 6.Kd2 Qe6 7.Qd5
>  ³  (-0.30)   Depth: 9/31   00:00:02  1415kN
>1.gxh5 Qg4+ 2.Kf2 Qf4+ 3.Ke2 gxh5 4.Qd5+ Kf6 5.Qd8+ Kg7 6.Qe7+ Qf7 7.Qg5+ Kh7
>8.Qg3 Qf6
>  ³  (-0.31)   Depth: 10/31   00:00:04  3235kN
>1.gxh5 Qg4+ 2.Kf2 gxh5 3.Qe5+ Kg6 4.Qd6+ Kf7 5.Qd5+ Ke7 6.Qb7+ Qd7 7.Qxb6 Qd2+
>8.Kg3 Qg5+ 9.Kf3 Qg4+ 10.Kf2 Qf4+ 11.Kg1
>  ³  (-0.34)   Depth: 11/34   00:00:12  8027kN
>1.Qe3+
>  ³  (-0.33)   Depth: 11/35   00:00:14  9406kN
>1.Qe3+
>  ³  (-0.63)   Depth: 12/37   00:00:19  12594kN
>1.Qe3+
>  µ  (-1.23)   Depth: 12/38   00:00:32  21277kN
>1.Qe3+ Kxg4 2.Qe2+ Kf4 3.Qf1+ Kg5 4.Qb5+ Kh6 5.Qd5 Qg5+ 6.Kh1 h4 7.e5 h3 8.Kh2
>Qf5 9.Qc4 Qxe5+ 10.Kxh3
>  -+  (-2.16)   Depth: 12/43   00:01:16  50741kN, tb=1
>1.gxh5
>  -+  (-2.15)   Depth: 12/43   00:01:23  55394kN, tb=1
>1.gxh5 Qg4+ 2.Kf2 gxh5 3.Qe5+ Kg6 4.Qd6+ Kf7 5.Qe5 Qg6 6.Qd5+ Ke7 7.Qb7+ Kf8
>8.Qd5 Qf6+ 9.Kg3 h4+ 10.Kh3
>  ³  (-0.48)   Depth: 12/43   00:01:39  66802kN, tb=2
>
>Correct move not found.
>
>
>>I'd like to get more input on this from
>>others.
>>I'll try the verified N.M one of these days.
>
>After the WCCC I will publish my improved version of verified null-move pruning
>when I get the time. I have changed several things in the original formulation
>to make the algorithm work more efficiently.
>
>
>
>>
>>Regards,
>>
>>  Jaime

I'm looking forward to read it; I already read your previous abstract on this



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