Author: Christophe Theron
Date: 11:24:34 04/08/98
Go up one level in this thread
On April 08, 1998 at 02:45:39, Bernhard Bauer wrote:
>On April 08, 1998 at 01:56:58, Christophe Theron wrote:
>
>>I think it's a zugzwang problem. I don't know exactly why, but it looks
>>like the black queen has to stay on the a1-h8 diagonal (or else the
>>white queen goes on this diagonal, check, and mate in 2), and has also
>>to stay on the the a file.
>>
>>Or something like that. Anyway, I think black is quickly caught in
>>zugzwang.
>>
>>Programs relying on null move like Fritz (and maybe Crafty?) have
>>problems with this, because a general rule in those programs is that
>>they don't care of zugzwang problem if the queens are on the board. This
>>is correct 99.99% of the time, but not in this position...
>>
>
>Here is some output from crafty:
>
>White(1): hash table memory = 6M bytes.
>White(1): pawn hash table memory = 1.3M bytes.
>
> +---+---+---+---+---+---+---+---+
> 8 | | | | | | | | *K|
> +---+---+---+---+---+---+---+---+
> 7 | | | | | K | | | *P|
> +---+---+---+---+---+---+---+---+
> 6 | | | | | | | | P |
> +---+---+---+---+---+---+---+---+
> 5 | | | | *P| | | Q | |
> +---+---+---+---+---+---+---+---+
> 4 | | | | | | | | |
> +---+---+---+---+---+---+---+---+
> 3 | | | | | | | | |
> +---+---+---+---+---+---+---+---+
> 2 | | | | | | | | |
> +---+---+---+---+---+---+---+---+
> 1 | *Q| | | | | | | |
> +---+---+---+---+---+---+---+---+
> a b c d e f g h
>
>White(1): end-game phase
> clearing hash tables
> time surplus 0.00 time limit 5:00 (5:00)
> depth time score variation (1)
> 6-> 0.84 0.29 1. Qf4 Qa7+ 2. Ke6 Qb6+ 3. Kxd5 Qb3+
> 4. Kc5 Qe6 5. Qf8+
> 7-> 1.79 0.00 1. Qf4 Qa7+ 2. Ke6 Qb6+ 3. Kxd5 Qb5+
> 4. Ke6 Qe8+ 5. Kf6 Qf8+ 6. Kg5 Qxf4+
> 7. Kxf4
> 8-> 3.70 0.12 1. Qe3 Qb2 2. Ke6 Qa1 3. Qb6 Qe1+ 4.
> Kxd5 Qd2+ 5. Ke5 Qd3
> 9-> 5.00 0.22 1. Qe3 Qb2 2. Ke6 Qa1 3. Qf4 Qa6+ 4.
> Ke5 Kg8 5. Kxd5 Qb6
> 10-> 9.78 0.00 1. Qe3 Qb2 2. Ke6 Qa1 3. Qf4 Qa6+ 4.
> Kxd5 Qb5+ 5. Ke6 Qe8+ 6. Kf6 Qf8+ 7.
> Kg5 Qxf4+ 8. Kxf4
> 11-> 16.43 0.00 1. Qe3 Qb2 2. Ke6 Qa1 3. Qf4 Qa6+ 4.
> Kxd5 Qb5+ 5. Ke6 Qe8+ 6. Kd5 Qf7+ 7.
> Qxf7
> 12 22.23 ++ 1. Qe3!!
> 12 29.48 Mat09 1. Qe3 Qb2 2. Ke6 Qa1 3. Qb6 Qg7 4.
> hxg7+ Kxg7 5. Kxd5 <EGTB>
> 12-> 47.53 Mat09 1. Qe3 Qb2 2. Ke6 Qa1 3. Qb6 Qg7 4.
> hxg7+ Kxg7 5. Kxd5 <EGTB>
> time: 47.54 cpu:0% mat:-1 n:4443263 nps:93444
> ext-> checks:825089 recaps:8581 pawns:15123 1rep:134501
> predicted:0 nodes:4443263 evals:370831
> endgame tablebase-> probes done: 37303 successful: 37303
> hashing-> trans/ref:63% pawn:99% used:w93% b99%
>
>Crafty will mate in 9 moves.
>
>So crafty seems to be pretty good on this problem.
>Kind regards
>B. Bauer
Crafty finds the solution with the endgame table bases (EGTB). This tell
us nothing about what it would to without them.
Can you turn the engame database off and try again?
Christophe
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