Author: Robert Hyatt
Date: 11:34:47 09/19/00
Go up one level in this thread
On September 14, 2000 at 22:41:07, Robert Hyatt wrote:
>On September 14, 2000 at 18:55:51, José de Jesús García Ruvalcaba wrote:
>
>>On September 14, 2000 at 18:44:03, Robert Hyatt wrote:
>>
>>
>>>>8/8/p2k3p/1P1p1pp1/P1r5/1R1K1PP1/7P/8 b - -
>>
>>>
>>>Yeah, right. Another reason to "love" netscape. When I did a cut and
>>>paste, it somehow didn't copy the entire FEN string. Leaving black with
>>>another pawn on the queenside that changes everything. Without the extra
>>>pawn it isn't hard to see (IMHO)... ie it is exactly what happens after
>>>an outside passed pawn has been used to decoy the enemy king away too far.
>>
>> But what does crafty think of this position?
>
>
>As I mentioned in another post, crafty has a "hole" here. IE if you move
>the black king one square from where it is, and put a white pawn on that
>square, the static eval says "white wins" because of the distant passer.
>But the instant the distant passer evaporates, the term goes away. In
>normal positions, this doesn't hurt a lot as by the time it has to give
>up the passer it can see that it wins pawns on the other side. But here
>it isn't so easy as black has a few horizon moves to throw in at key times.
>
>I almost have this fixed, finally, which will likely let it find a5 almost
>instantly since king moves lose and the axb5 evaporates the queenside with
>white's king too close to stop on the kingside.
As promised, I finally found a bit of time to fix this "hole". Here is the
result:
(3) 7 0.40 -1.01 1. ... axb5 2. axb5 Rc7 3. b6 Rb7 4.
Kd4 h5 5. h4
(2) 7-> 0.65 -1.01 1. ... axb5 2. axb5 Rc7 3. b6 Rb7 4.
Kd4 h5 5. h4
8 0.78 -1.05 1. ... axb5 2. axb5 Rc7 3. b6 Rb7 4.
Kd4 g4 5. fxg4 fxg4 6. Rb5
8 1.25 -1.02 1. ... a5 2. b6 Rb4 3. Rxb4 axb4 4.
h4 b3 5. b7 Kc7 6. hxg5 hxg5
(4) 8-> 1.29 -1.02 1. ... a5 2. b6 Rb4 3. Rxb4 axb4 4.
h4 b3 5. b7 Kc7 6. hxg5 hxg5
(3) 9 1.52 -1.04 1. ... a5 2. b6 Rb4 3. Rxb4 axb4 4.
Kc2 Kc6 5. a5 g4 6. f4
(2) 9 1.89 -1.01 1. ... axb5 2. axb5 Rc7 3. b6 Rb7 4.
Kd4 h5 5. Rb5 Ke6 6. h4
9-> 2.45 -1.01 1. ... axb5 2. axb5 Rc7 3. b6 Rb7 4.
Kd4 h5 5. Rb5 Ke6 6. h4
10 3.02 -1.03 1. ... axb5 2. axb5 Rc7 3. b6 Rb7 4.
Kd4 g4 5. f4 h5 6. Rb5 Ke6
(4) 10-> 5.93 -1.03 1. ... axb5 2. axb5 Rc7 3. b6 Rb7 4.
Kd4 g4 5. f4 h5 6. Rb5 Ke6
(3) 11 7.25 -1.01 1. ... axb5 2. axb5 Rc7 3. b6 Rb7 4.
Kd4 g4 5. f4 Kc6 6. Ke5 Rb8 7. Kxf5
Rxb6 8. Rxb6+ Kxb6 9. Kxg4
11 10.12 -0.93 1. ... a5 2. b6 Rb4 3. Rxb4 axb4 4.
a5 Kc6 5. h4 gxh4 6. gxh4 Kb7 7. Kd4
b3
(2) 11-> 13.38 -0.93 1. ... a5 2. b6 Rb4 3. Rxb4 axb4 4.
a5 Kc6 5. h4 gxh4 6. gxh4 Kb7 7. Kd4
b3
12 16.39 -0.93 1. ... a5 2. b6 Rb4 3. Rxb4 axb4 4.
a5 Kc6 5. h4 Kb7 6. hxg5 hxg5 7. Kc2
f4 8. gxf4 gxf4
(4) 12-> 29.52 -0.93 1. ... a5 2. b6 Rb4 3. Rxb4 axb4 4.
a5 Kc6 5. h4 Kb7 6. hxg5 hxg5 7. Kc2
f4 8. gxf4 gxf4
And for the next 30 minutes, it hever changes from a5. The problem was that
it realized that the outside passer would win, but in this position, the
outside passer disappears as soon as it is created, leaving the black king
in a lost K+P ending position. Crafty now understands what goes on after
the outside passer goes away, where the white king is too close to the black
pawns, even though the search doesn't see it for quite a while. The evaluation
"knows" now...
Plenty of other such "holes" are left I am sure, but it has become pretty
dangerous in the endgame over the last couple of years... to the point that
I _never_ mind seeing it trade into an ending vs a GM. It usually knows what
it is doing.
Sometime when we have nothing else to discuss here I will post a few positions
(without the names of the programs to avoid embarassing the guilty) that shows
just how bad some programs do in classic endings, while being in the top group
of 10 or so on the SSDF list. IE more than one "top" program knows nothing
at all about outside passed pawns. Nor pawn majorities that represent potential
outside passed pawns. I don't believe you can compete with GMs regularly with
that sort of "hole".
More later...
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