Author: Bernhard Bauer
Date: 05:13:36 02/04/00
Go up one level in this thread
On February 04, 2000 at 05:33:53, Georg Langrath wrote:
Hi George,
>3n4/8/pppN4/k7/2P5/1K6/P7/8 w
>
>About this position. Fritz 5.32 can't find this mate in three. Fritz 6 can find
>it in time mode, but not in analyze mode. In my opinion that is an ugly bug.
you are perfectly right, of course.
>
>Then somebody says that it is a null-move problem. Then no more with that. When
>it is a null-move problem is seems as it is acceptable in the world of
>chesscomputers and no more to add. In my opinion it is still very ugly that a
>modern chesscomputer can't find a mate in three.
>
It's a general attitude in the computerchess comunity not to deal with null move
problems. If a programmer implements the null move technique it's programs
strength will considerably rise. Now null move problems will no longer be
detected - they do no longer exist to the program. So the programmer tends to
think that null move problems exist only in studies, but he wants his program to
play reasonable chess. That's something different, for him.
Yes, it's ugly. But it's not the computer, it's the software.
You may consider Crafty. It solves your position easyly. Here Crafty's output:
White(1): end-game phase
clearing hash tables
time surplus 0.00 time limit 16:40 (16:40)
nss depth time score variation (1)
starting thread 1
1 0.11 -0.75 1. a3
1-> 0.13 -0.75 1. a37+
2 0.13 -0.90 1. a3 Ne6
2-> 0.13 -0.90 1. a3 Ne6
3 0.13 -0.99 1. a3 b5 2. c5
3 0.13 -0.97 1. Ne4 Nf7 2. Nf6
3 0.13 -0.67 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5c8
3-> 0.14 -0.67 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5
4 0.14 -0.67 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5
4-> 0.14 -0.67 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5
5 0.14 -0.67 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5
5-> 0.16 -0.67 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5
6 0.16 ++ 1. a4!!
6-> 0.16 -0.28 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5
7 0.17 -- 1. a4
7 0.24 0.00 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5
<EGTB>
7-> 0.25 0.00 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5
<EGTB>
8 0.33 0.00 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5
<EGTB>
(2) 8-> 0.39 0.00 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5
<EGTB>
9 0.50 0.00 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5
<EGTB>
9-> 0.60 0.00 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5
<EGTB>
10 0.83 0.00 1. a4 b5 2. cxb5 axb5 3. axb5 cxb5
<EGTB>
10 1.08 ++ 1. c5!!
10 1.17 Mat03 1. c5 bxc5 2. Nc4+ Kb5 3. a4#
10-> 1.17 Mat03 1. c5 bxc5 2. Nc4+ Kb5 3. a4#
time=1.33 cpu=1540% mat=-1 n=80995 fh=96% nps=61359
ext-> checks=3003 recaps=492 pawns=50 1rep=209 thrt:16
predicted=0 nodes=80995 evals=9141
endgame tablebase-> probes done=183 successful=180
hashing-> trans/ref=53% pawn=98% used=1%
SMP-> split=94 stop=11 data=4/64 cpu=20.33 elap=1.32
mate in 3 moves.
whisper mate in 3 moves.
>I think that it is done before, but can somebody explain this mystical null-move
>so also an amateur understands? I think it is some kind of holy magic power that
>you must not heckle.
>
>Georg
This has been done by other posters.
Kind regards
Bernhard
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