Funny fortress position

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Oratios

Re: Funny fortress position

Post by Oratios »

An excelent paper on the subjetct by Omid Tabibi, Ariel Felner and Nathan Netanyahu:
http://www.ise.bgu.ac.il/faculty/felner ... ckagej.pdf
Thanks Richard. Very useful.
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Edmund
Posts: 670
Joined: Mon Dec 03, 2007 3:01 pm
Location: Barcelona, Spain

Re: Funny fortress position

Post by Edmund »

rvida wrote:
Edmund wrote:
rvida wrote:SOS has special code to detect blocked positions.
Has anyone got any ideas how this could be done? I know about corresponding squares, but this doesn't apply here with the pieces adding complexity.

regards,
Edmund
An excelent paper on the subjetct by Omid Tabibi, Ariel Felner and Nathan Netanyahu:
http://www.ise.bgu.ac.il/faculty/felner ... ckagej.pdf
Thanks for the link,

I implemented a corresponding squares algorithm into Glass. This is quite similar to the paper you presented. But both have in common that there are no pieces on the board.

The knowledge needed for the position given here is much harder to generalize in my opinion. You always have to be aware of possible queen sacs to create an unstoppable passer etc.

regards,
Edmund
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George Tsavdaris
Posts: 1627
Joined: Thu Mar 09, 2006 12:35 pm

Re: Funny fortress position

Post by George Tsavdaris »

Edmund wrote:
rvida wrote:
Edmund wrote:
rvida wrote:SOS has special code to detect blocked positions.
Has anyone got any ideas how this could be done? I know about corresponding squares, but this doesn't apply here with the pieces adding complexity.

regards,
Edmund
An excelent paper on the subjetct by Omid Tabibi, Ariel Felner and Nathan Netanyahu:
http://www.ise.bgu.ac.il/faculty/felner ... ckagej.pdf
Thanks for the link,

I implemented a corresponding squares algorithm into Glass. This is quite similar to the paper you presented. But both have in common that there are no pieces on the board.

The knowledge needed for the position given here is much harder to generalize in my opinion. You always have to be aware of possible queen sacs to create an unstoppable passer etc.
Perhaps SOS just see a draw for wrong reasons. So perhaps in a similar position but that white has a trick to make which wins, SOS would still report a 0.00 but it would be wrong.

To increase the confusion, SOS-5 when it runs inside Arena 1.1 gives everything 0.00 from ply 1, but when it runs inside Chessbase it says +3.53 for white. :? :? Hmm.... :?

FEN: 4kb2/2p3r1/1pP1P2Q/pP2K3/P7/8/8/8 w - - 0 93

IN ARENA 1.1
SOS 5 for Arena:
1/6 00:00 261 0 0,00 93.Kd4
2/6 00:00 263 0 0,00 93.Kd4
3/6 00:00 302 0 0,00 93.Kd4
4/6 00:00 349 0 0,00 93.Kd4
5/8 00:00 430 0 0,00 93.Kd4
6/8 00:00 566 0 0,00 93.Kd4
7/10 00:00 824 0 0,00 93.Kd4
8/12 00:00 1.218 0 0,00 93.Kd4
9/12 00:00 1.848 0 0,00 93.Kd4
10/14 00:00 2.737 0 0,00 93.Kd4
11/14 00:00 4.155 0 0,00 93.Kd4
12/16 00:00 6.374 0 0,00 93.Kd4
13/18 00:00 8.951 0 0,00 93.Kd4
14/19 00:00 12.789 0 0,00 93.Kd4
15/19 00:00 15.351 0 0,00 93.Kd4
16/19 00:00 18.358 0 0,00 93.Kd4
17/20 00:00 24.107 0 0,00 93.Kd4
18/21 00:00 30.473 0 0,00 93.Kd4
19/22 00:00 38.049 0 0,00 93.Kd4
20/25 00:00 48.109 0 0,00 93.Kd4
21/25 00:00 64.463 0 0,00 93.Kd4
22/26 00:00 94.784 0 0,00 93.Kd4
23/27 00:00 107.880 0 0,00 93.Kd4
24/29 00:00 137.550 0 0,00 93.Kd4
25/29 00:00 157.582 0 0,00 93.Kd4
26/31 00:00 185.401 0 0,00 93.Kd4
27/34 00:00 216.760 0 0,00 93.Kd4
28/34 00:00 315.615 0 0,00 93.Kd4
29/36 00:00 359.838 0 0,00 93.Kd4
30/36 00:01 472.472 0 0,00 93.Kd4
31/37 00:01 540.347 0 0,00 93.Kd4
32/38 00:01 634.920 0 0,00 93.Kd4
33/40 00:01 763.806 0 0,00 93.Kd4
34/41 00:01 925.643 0 0,00 93.Kd4
35/42 00:02 1.141.306 0 0,00 93.Kd4
36/45 00:02 1.446.053 0 0,00 93.Kd4
Best move: Kd4, Value: 0,00, Depth: 36/45, Time: 00:03,338, 1.446.053 Nodes


IN CHESSBASE:
Analysis by SOS 5 for Arena:

1.Qh6-f6 Rg7-e7 2.Qf6-h8 Re7-g7 3.Qh8-h5+ Ke8-d8 4.Qh5-f5 Bf8-d6+
+- (3.54) Depth: 6/15 00:00:00 8kN
1.Qh6-f6 Rg7-e7 2.Qf6-h8 Re7-g7 3.Qh8-h5+ Ke8-d8 4.Qh5-h4+ Rg7-e7 5.Qh4-h8 Re7-e8
+- (3.54) Depth: 7/17 00:00:00 18kN
1.Ke5-d5 Rg7-e7 2.Qh6-h8 Re7-g7 3.Qh8-h5+ Ke8-d8 4.Qh5-f5 Bf8-e7 5.Qf5-e5
+- (3.53) Depth: 8/17 00:00:00 33kN
1.Qh6-f6 Rg7-e7 2.Qf6-h8 Re7-g7 3.Qh8-h5+ Ke8-d8 4.Ke5-f6 Rg7-e7 5.Qh5-h8 Re7-e8 6.Kf6-f7 Re8-e7+ 7.Kf7xf8 Re7-e8+
+- (3.53) Depth: 9/18 00:00:00 50kN
1.Qh6-f6 Rg7-e7 2.Qf6-h8 Re7-g7 3.Ke5-f6 Rg7-e7 4.Kf6-e5
+- (3.53) Depth: 10/18 00:00:00 52kN
1.Qh6-f6 Rg7-e7 2.Qf6-h8 Re7-g7 3.Ke5-f6 Rg7-e7 4.Kf6-f5 Re7-g7 5.Qh8-h5+ Ke8-d8 6.Kf5-f6 Rg7-e7 7.Qh5-h8 Re7-e8 8.Kf6-f7 Re8-e7+ 9.Kf7xf8 Re7-e8+
+- (3.53) Depth: 11/23 00:00:01 142kN
1.Qh6-f6 Rg7-e7 2.Qf6-h8 Re7-g7 3.Ke5-f6 Rg7-e7 4.Kf6-f5 Re7-g7 5.Qh8-h5+ Ke8-d8 6.Kf5-f6 Rg7-e7 7.Qh5-h8 Re7-e8 8.Kf6-f7 Re8-e7+ 9.Kf7xf8 Re7-e8+
+- (3.53) Depth: 12/27 00:00:01 269kN
1.Qh6-f6 Rg7-e7 2.Qf6-h8 Re7-g7 3.Ke5-f6 Rg7-e7 4.Kf6-f5 Re7-g7 5.Qh8-h5+ Ke8-d8 6.Kf5-f6 Rg7-e7 7.Qh5-h8 Re7-e8 8.Kf6-f7 Re8-e7+ 9.Kf7xf8 Re7-e8+
+- (3.53) Depth: 13/27 00:00:01 444kN
1.Ke5-d5 Rg7-e7 2.Qh6-h5+ Ke8-d8 3.Qh5-h8 Re7-e8 4.e6-e7+ Bf8xe7 5.Qh8-h3
+- (3.53) Depth: 14/27 00:00:01 557kN
1.Ke5-d5 Rg7-e7 2.Qh6-h5+ Ke8-d8 3.Qh5-h8 Kd8-e8 4.Kd5-e5 Re7-g7 5.Ke5-f6 Rg7-e7 6.Kf6-f5 Re7-g7 7.Qh8-h5+ Ke8-d8 8.Kf5-f6 Rg7-e7 9.Qh5-h8 Re7-e8 10.Kf6-f7 Re8-e7+ 11.Kf7xf8 Re7-e8+
+- (3.53) Depth: 15/27 00:00:02 761kN
1.Qh6-h5+ Ke8-d8 2.Qh5-h8 Kd8-e8 3.Ke5-f6 Rg7-e7 4.Kf6-e5 Re7-g7
+- (3.53) Depth: 16/31 00:00:03 1498kN
1.Ke5-d5 Rg7-e7 2.Qh6-h5+ Ke8-d8 3.Qh5-h8 Kd8-e8 4.Kd5-c4 Re7xe6 5.Qh8-h5+ Ke8-d8 6.Qh5-d5+ Re6-d6 7.Qd5-f7 Bf8-h6 8.Qf7-g8+ Kd8-e7 9.Qg8-b8
+- (3.53) Depth: 17/32 00:00:05 2837kN
1.Ke5-d5 Rg7-e7 2.Qh6-h5+ Ke8-d8 3.Qh5-h8 Kd8-e8 4.Kd5-c4 Re7-g7 5.Qh8-h5+ Ke8-d8 6.Qh5-h4+ Rg7-e7 7.Qh4-h8 Kd8-e8
+- (3.53) Depth: 18/33 00:00:06 3539kN
1.Ke5-d5 Rg7-e7 2.Qh6-h5+ Ke8-d8 3.Qh5-h8 Kd8-e8 4.Kd5-c4 Re7-g7 5.Qh8-h5+ Ke8-d8 6.Qh5-h4+ Rg7-e7 7.Qh4-h8 Kd8-e8
+- (3.53) Depth: 19/35 00:00:08 4768kN, tb=1
1.Ke5-d5 Rg7-e7 2.Qh6-h5+ Ke8-d8 3.Qh5-h8 Kd8-e8 4.Kd5-c4 Re7-g7 5.Qh8-h5+ Ke8-d8 6.Qh5-h4+ Rg7-e7 7.Qh4-h8 Kd8-e8
+- (3.53) Depth: 20/36 00:00:10 6670kN, tb=2
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Edmund
Posts: 670
Joined: Mon Dec 03, 2007 3:01 pm
Location: Barcelona, Spain

Re: Funny fortress position

Post by Edmund »

George Tsavdaris wrote:
Edmund wrote:
rvida wrote:
Edmund wrote:
rvida wrote:SOS has special code to detect blocked positions.
Has anyone got any ideas how this could be done? I know about corresponding squares, but this doesn't apply here with the pieces adding complexity.

regards,
Edmund
An excelent paper on the subjetct by Omid Tabibi, Ariel Felner and Nathan Netanyahu:
http://www.ise.bgu.ac.il/faculty/felner ... ckagej.pdf
Thanks for the link,

I implemented a corresponding squares algorithm into Glass. This is quite similar to the paper you presented. But both have in common that there are no pieces on the board.

The knowledge needed for the position given here is much harder to generalize in my opinion. You always have to be aware of possible queen sacs to create an unstoppable passer etc.
Perhaps SOS just see a draw for wrong reasons. So perhaps in a similar position but that white has a trick to make which wins, SOS would still report a 0.00 but it would be wrong.

To increase the confusion, SOS-5 when it runs inside Arena 1.1 gives everything 0.00 from ply 1, but when it runs inside Chessbase it says +3.53 for white. :? :? Hmm.... :?
(...)
Must be a different version you are using (or different settings) or something is wrong with your chessbase. This is what I get if I enter everything in the console:
uci
id name SOS 5 for Arena
id author Rudolf Huber
option name NalimovPath type string default <empty>
option name ClearHash type button
option name MultiPV type spin default 1 min 1 max 64
option name NalimovCache type spin default 1 min 1 max 64
option name Hash type spin default 0 min 0 max 1024
option name Nullmove type check default true
option name Material only type check default false
option name Ponder type check default true
option name UseNalimov type check default true
option name Brute Force type check default false
option name OwnBook type check default true
uciok
position fen 4kb2/2p3r1/1pP1P2Q/pP2K3/P7/8/8/8 w - - 0 93
go depth 10
info depth 1 seldepth 0
info score cp 0 depth 1 seldepth 6 nodes 261 time 0 pv e5d4
info depth 1 seldepth 6
info depth 2 seldepth 6
info score cp 0 depth 2 seldepth 6 nodes 263 time 0 pv e5d4
info depth 2 seldepth 6
info depth 3 seldepth 6
info score cp 0 depth 3 seldepth 6 nodes 302 time 0 pv e5d4
info depth 3 seldepth 6
info depth 4 seldepth 6
info score cp 0 depth 4 seldepth 6 nodes 349 time 0 pv e5d4
info depth 4 seldepth 8
info depth 5 seldepth 8
info score cp 0 depth 5 seldepth 8 nodes 430 time 0 pv e5d4
info depth 5 seldepth 8
info depth 6 seldepth 8
info currmove e5d4 currmovenumber 1
info score cp 0 depth 6 seldepth 8 nodes 566 time 16 pv e5d4
info score cp 0
info currmove e5d4 currmovenumber 1
info currmove h6g7 currmovenumber 2
info currmove e6e7 currmovenumber 3
info currmove e5d5 currmovenumber 4
info currmove e5f6 currmovenumber 5
info currmove e5e4 currmovenumber 6
info currmove e5f5 currmovenumber 7
info currmove h6c1 currmovenumber 8
info currmove h6d2 currmovenumber 9
info currmove h6e3 currmovenumber 10
info currmove h6f4 currmovenumber 11
info currmove h6g5 currmovenumber 12
info currmove e5f4 currmovenumber 13
info currmove h6h1 currmovenumber 14
info currmove h6h2 currmovenumber 15
info currmove h6h3 currmovenumber 16
info currmove h6h4 currmovenumber 17
info currmove h6h5 currmovenumber 18
info currmove h6f6 currmovenumber 19
info currmove h6g6 currmovenumber 20
info currmove h6h8 currmovenumber 21
info currmove h6h7 currmovenumber 22
info score cp -1
info depth 6 seldepth 10
info depth 7 seldepth 10
info currmove e5d4 currmovenumber 1
info score cp 0 depth 7 seldepth 10 nodes 824 time 16 pv e5d4
info score cp 0
info currmove e5d4 currmovenumber 1
info currmove h6g7 currmovenumber 2
info currmove e6e7 currmovenumber 3
info currmove e5d5 currmovenumber 4
info currmove e5f6 currmovenumber 5
info currmove e5e4 currmovenumber 6
info currmove e5f5 currmovenumber 7
info currmove h6c1 currmovenumber 8
info currmove h6d2 currmovenumber 9
info currmove h6e3 currmovenumber 10
info currmove h6f4 currmovenumber 11
info currmove h6g5 currmovenumber 12
info currmove e5f4 currmovenumber 13
info currmove h6h1 currmovenumber 14
info currmove h6h2 currmovenumber 15
info currmove h6h3 currmovenumber 16
info currmove h6h4 currmovenumber 17
info currmove h6h5 currmovenumber 18
info currmove h6f6 currmovenumber 19
info currmove h6g6 currmovenumber 20
info currmove h6h8 currmovenumber 21
info currmove h6h7 currmovenumber 22
info score cp -1
info depth 7 seldepth 12
info depth 8 seldepth 12
info currmove e5d4 currmovenumber 1
info score cp 0 depth 8 seldepth 12 nodes 1218 time 31 pv e5d4
info score cp 0
info currmove e5d4 currmovenumber 1
info currmove h6g7 currmovenumber 2
info currmove e6e7 currmovenumber 3
info currmove e5d5 currmovenumber 4
info currmove e5f6 currmovenumber 5
info currmove e5e4 currmovenumber 6
info currmove e5f5 currmovenumber 7
info currmove h6c1 currmovenumber 8
info currmove h6d2 currmovenumber 9
info currmove h6e3 currmovenumber 10
info currmove h6f4 currmovenumber 11
info currmove h6g5 currmovenumber 12
info currmove e5f4 currmovenumber 13
info currmove h6h1 currmovenumber 14
info currmove h6h2 currmovenumber 15
info currmove h6h3 currmovenumber 16
info currmove h6h4 currmovenumber 17
info currmove h6h5 currmovenumber 18
info currmove h6f6 currmovenumber 19
info currmove h6g6 currmovenumber 20
info currmove h6h8 currmovenumber 21
info currmove h6h7 currmovenumber 22
info score cp -1
info depth 8 seldepth 12
info depth 9 seldepth 12
info currmove e5d4 currmovenumber 1
info score cp 0 depth 9 seldepth 12 nodes 1848 time 47 pv e5d4
info score cp 0
info currmove e5d4 currmovenumber 1
info currmove h6g7 currmovenumber 2
info currmove e6e7 currmovenumber 3
info currmove e5d5 currmovenumber 4
info currmove e5f6 currmovenumber 5
info currmove e5e4 currmovenumber 6
info currmove e5f5 currmovenumber 7
info currmove h6c1 currmovenumber 8
info currmove h6d2 currmovenumber 9
info currmove h6e3 currmovenumber 10
info currmove h6f4 currmovenumber 11
info currmove h6g5 currmovenumber 12
info currmove e5f4 currmovenumber 13
info currmove h6h1 currmovenumber 14
info currmove h6h2 currmovenumber 15
info currmove h6h3 currmovenumber 16
info currmove h6h4 currmovenumber 17
info currmove h6h5 currmovenumber 18
info currmove h6f6 currmovenumber 19
info currmove h6g6 currmovenumber 20
info currmove h6h8 currmovenumber 21
info currmove h6h7 currmovenumber 22
info score cp -1
info depth 9 seldepth 14
info depth 10 seldepth 14
info currmove e5d4 currmovenumber 1
info score cp 0 depth 10 seldepth 14 nodes 2737 time 63 pv e5d4
info score cp 0
info currmove e5d4 currmovenumber 1
info currmove h6g7 currmovenumber 2
info currmove e6e7 currmovenumber 3
info currmove e5d5 currmovenumber 4
info currmove e5f6 currmovenumber 5
info currmove e5e4 currmovenumber 6
info currmove e5f5 currmovenumber 7
info currmove h6c1 currmovenumber 8
info currmove h6d2 currmovenumber 9
info currmove h6e3 currmovenumber 10
info currmove h6f4 currmovenumber 11
info currmove h6g5 currmovenumber 12
info currmove e5f4 currmovenumber 13
info currmove h6h1 currmovenumber 14
info currmove h6h2 currmovenumber 15
info currmove h6h3 currmovenumber 16
info currmove h6h4 currmovenumber 17
info currmove h6h5 currmovenumber 18
info currmove h6f6 currmovenumber 19
info currmove h6g6 currmovenumber 20
info currmove h6h8 currmovenumber 21
info currmove h6h7 currmovenumber 22
info score cp -1
info depth 10 seldepth 14
info cpuload 238
bestmove e5d4
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George Tsavdaris
Posts: 1627
Joined: Thu Mar 09, 2006 12:35 pm

Re: Funny fortress position

Post by George Tsavdaris »

Edmund wrote:
George Tsavdaris wrote:
Edmund wrote:
rvida wrote:
Edmund wrote:
rvida wrote:SOS has special code to detect blocked positions.
Has anyone got any ideas how this could be done? I know about corresponding squares, but this doesn't apply here with the pieces adding complexity.

regards,
Edmund
An excelent paper on the subjetct by Omid Tabibi, Ariel Felner and Nathan Netanyahu:
http://www.ise.bgu.ac.il/faculty/felner ... ckagej.pdf
Thanks for the link,

I implemented a corresponding squares algorithm into Glass. This is quite similar to the paper you presented. But both have in common that there are no pieces on the board.

The knowledge needed for the position given here is much harder to generalize in my opinion. You always have to be aware of possible queen sacs to create an unstoppable passer etc.
Perhaps SOS just see a draw for wrong reasons. So perhaps in a similar position but that white has a trick to make which wins, SOS would still report a 0.00 but it would be wrong.

To increase the confusion, SOS-5 when it runs inside Arena 1.1 gives everything 0.00 from ply 1, but when it runs inside Chessbase it says +3.53 for white. :? :? Hmm.... :?
(...)
Must be a different version you are using (or different settings) or something is wrong with your chessbase. This is what I get if I enter everything in the console:
There is nothing wrong with my Chessbase(it was "Fritz" GUI that came with Rybka 3).
The problem as i see lies in the FEN. As i see Chessbase gets the FEN with 0 93 values and converts it to 0 1 values of halfmove clock and fullmove number.

And apparently SOS handles completely different the following identical positions with different halfmove clock and fullmove number, numbers:

4kb2/2p3r1/1pP1P2Q/pP2K3/P7/8/8/8 w - - 0 93
4kb2/2p3r1/1pP1P2Q/pP2K3/P7/8/8/8 w - - 0 1

Try SOS at these. In the first shows a draw in the second the +3.53 i have shown.
Any idea why it does that?
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"Is it a boy or girl?"
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Edmund
Posts: 670
Joined: Mon Dec 03, 2007 3:01 pm
Location: Barcelona, Spain

Re: Funny fortress position

Post by Edmund »

George Tsavdaris wrote:There is nothing wrong with my Chessbase(it was "Fritz" GUI that came with Rybka 3).
The problem as i see lies in the FEN. As i see Chessbase gets the FEN with 0 93 values and converts it to 0 1 values of halfmove clock and fullmove number.

And apparently SOS handles completely different the following identical positions with different halfmove clock and fullmove number, numbers:

4kb2/2p3r1/1pP1P2Q/pP2K3/P7/8/8/8 w - - 0 93
4kb2/2p3r1/1pP1P2Q/pP2K3/P7/8/8/8 w - - 0 1

Try SOS at these. In the first shows a draw in the second the +3.53 i have shown.
Any idea why it does that?
nice finding

seems like SOS mixes up the last two fen tags. If I run the same position with halfmove to last capture/pawn move set to 98 and the fullmove counter set to 1 it also returns a positive score of >3.5cp. Anyway the draw could only be avoided by sacrificing either queen or pawn and this doesn't show up in the PV.
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Teemu Pudas
Posts: 88
Joined: Wed Mar 25, 2009 12:49 pm

Re: Funny fortress position

Post by Teemu Pudas »

zamar wrote:
Michael Diosi wrote:Hi,

Code: Select all

FEN: 4kb2/2p3r1/1pP1P2Q/pP2K3/P7/8/8/8 w - - 0 93 

SOS 5.1 for Arena:
  1/6	00:00	         261	0	 0,00	1.Ke5d4

[/quote]

Vow! How on earth it's able to spot this???[/quote]

Wait, [i]what?[/i] Kd4 just loses the queen.
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Vinvin
Posts: 5228
Joined: Thu Mar 09, 2006 9:40 am
Full name: Vincent Lejeune

Re: Funny fortress position

Post by Vinvin »

zamar wrote: ↑Mon Jan 25, 2010 2:02 pm In Stockfish's self-play there occured a funny fortress position:

[d]4kb2/2p3r1/1pP1P2Q/pP2K3/P7/8/8/8 w - - 0 93

Stockfish shows this as +4 for white. How about your favourite engine?
Blast from the past.
Which engine gives an eval under 0.5 here ?
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zullil
Posts: 6442
Joined: Tue Jan 09, 2007 12:31 am
Location: PA USA
Full name: Louis Zulli

Re: Funny fortress position

Post by zullil »

Vinvin wrote: ↑Wed Feb 12, 2020 10:53 am
zamar wrote: ↑Mon Jan 25, 2010 2:02 pm In Stockfish's self-play there occured a funny fortress position:

[d]4kb2/2p3r1/1pP1P2Q/pP2K3/P7/8/8/8 w - - 0 93

Stockfish shows this as +4 for white. How about your favourite engine?
Blast from the past.
Which engine gives an eval under 0.5 here ?
Here's Stockfish-dev's static evaluation. A nice reminder of how far even top engines are from providing perfect guidance.

Code: Select all

$ ./stockfish 
Stockfish 120220 64 BMI2 by T. Romstad, M. Costalba, J. Kiiski, G. Linscott
position fen 4kb2/2p3r1/1pP1P2Q/pP2K3/P7/8/8/8 w - - 0 93
d

 +---+---+---+---+---+---+---+---+
 |   |   |   |   | k | b |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   | p |   |   |   | r |   |
 +---+---+---+---+---+---+---+---+
 |   | p | P |   | P |   |   | Q |
 +---+---+---+---+---+---+---+---+
 | p | P |   |   | K |   |   |   |
 +---+---+---+---+---+---+---+---+
 | P |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+

Fen: 4kb2/2p3r1/1pP1P2Q/pP2K3/P7/8/8/8 w - - 0 93
Key: 7211D1CF3CD066F6
Checkers: 
eval
     Term    |    White    |    Black    |    Total   
             |   MG    EG  |   MG    EG  |   MG    EG 
 ------------+-------------+-------------+------------
    Material |  ----  ---- |  ----  ---- |  2.08  3.69
   Imbalance |  ----  ---- |  ----  ---- |  0.13  0.13
       Pawns |  0.43  0.05 |  0.25 -0.08 |  0.18  0.12
     Knights |  0.00  0.00 |  0.00  0.00 |  0.00  0.00
     Bishops |  0.00  0.00 | -0.12 -0.23 |  0.12  0.23
       Rooks |  0.00  0.00 |  0.22  0.12 | -0.22 -0.12
      Queens | -0.23 -0.07 |  0.00  0.00 | -0.23 -0.07
    Mobility |  0.33  0.62 |  0.39  0.92 | -0.06 -0.30
 King safety | -0.56 -0.15 | -3.50 -0.53 |  2.94  0.38
     Threats |  0.16  0.16 |  0.16  0.16 |  0.00  0.00
      Passed |  0.63  0.55 |  0.00  0.00 |  0.63  0.55
       Space |  0.00  0.00 |  0.00  0.00 |  0.00  0.00
  Initiative |  ----  ---- |  ----  ---- |  0.00 -0.03
 ------------+-------------+-------------+------------
       Total |  ----  ---- |  ----  ---- |  5.58  4.59

Total evaluation: 4.99 (white side)
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MikeB
Posts: 4889
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Location: Pen Argyl, Pennsylvania

Re: Funny fortress position

Post by MikeB »

zamar wrote: ↑Mon Jan 25, 2010 2:02 pm In Stockfish's self-play there occured a funny fortress position:

[d]4kb2/2p3r1/1pP1P2Q/pP2K3/P7/8/8/8 w - - 0 93

Stockfish shows this as +4 for white. How about your favourite engine?
Black Diamond XI has Joe Ellis' fortress detection code built in.

Code: Select all

dep	score	time	(not shown:  nodes	tbhits	knps	seldep	)
 26	  0.00 	0:17.90	Kd8 e7+ Kxe7 Qh3 Kd8 Qf5 Bc5 Ke5 Bd6+ Kf6 Re7 Kg6 Be5 Qf8+ Re8 Qf7 Re7
 25	  0.00 	0:06.35	Kd8 e7+ Kxe7 Qh3 Kd8 Qf5 Bc5 Ke5 Bd6+ Kf6 Re7 Kg6 Be5 Qf8+ Re8 Qf7 Re7
 24	  0.00 	0:03.64	Kd8 e7+ Kxe7 Qh3 Kd8 Qf5 Bc5 Ke5 Bd6+ Kf6 Re7 Kg6 Bb4 Qf8+ Re8 Qf7 Re7
 23	  0.00 	0:01.37	Kd8 e7+ Kxe7 Qh3 Kd8 Qf5 Bc5 Ke5 Bd6+ Kf6 Re7 Kg6 Bb4 Qf8+ Re8 Qf7 Re7
 22	  0.00 	0:01.00	Kd8 e7+ Kxe7 Qh3 Kd8 Qf5 Bc5 Ke5 Bd6+ Kf6 Re7 Kg6 Be5 Qf8+ Re8 Qf7 Re7
 21	  0.00 	0:00.70	Kd8 e7+ Kxe7 Qh3 Kd8 Qf5 Bc5 Ke5 Bd6+ Kf6 Re7 Kg6 Be5 Qf8+ Re8 Qf7 Re7
 20	  0.00 	0:00.53	Kd8 e7+ Kxe7 Qh3 Kd8 Qf5 Bc5 Ke5 Bd6+ Kf6 Bf8 Qd3+ Ke8 Qd5 Re7 Qa2 Kd8 Kg6 Rg7+ Kf6
 19	  0.00 	0:00.48	Kd8 e7+ Kxe7 Qh4+ Ke8 Qh5+ Kd8 Qh3 Re7 Qh8 Ke8 Qh5+ Kd8
 18	  0.00 	0:00.30	Re7 Qh5+ Kd8 Qf5 Ke8
 17	  0.00 	0:00.27	Re7 Qh5+ Kd8 Qf5 Ke8
 16	  0.00 	0:00.25	Re7 Qh5+ Kd8 Qf5 Ke8
 15	  0.00 	0:00.20	Re7 Qh5+ Kd8 Qh8 Ke8
 14	 -0.80 	0:00.10	Kd8 Qf6+ Ke8 Qh4 Re7 Qh5+ Kd8 Qh8 Ke8 Kc4 Rg7 e7 Rxe7 Kd5 Rg7 Qh5+ Kd8 Qf5 Bd6 Qf6+ Re7 Kc4 Ke8 Qh8+ Kf7 Qh5+ Kg7 Qf5 Re5 Qb1
 13	 -1.05 	0:00.08	Kd8 Qf6+ Ke8 Qh4 Re7 Qh8 Rg7 Qh5+ Ke7 Qh4+ Ke8 Kd4 Re7 Qh8 Rg7 Qh5+ Kd8 Qd5+ Ke8 e7 Rxe7 Qh5+ Kd8 Qh8 Ke8 Kd5 Rg7 Qh5+ Kd8 Qf5 Bd6 Qf6+ Re7 Kc4 Ke8 Qh8+ Kf7
 12	 -0.69 	0:00.06	Re7 Qh5+ Kd8 Qh8 Ke8 Kc4 Rg7 e7 Kxe7 Qh5 Kd8 Qf5 Bd6 Qf6+ Re7 Kd3 Be5 Qf8+ Re8 Qf7 Re7 Qg8+ Re8 Qg5+ Re7 Kc4 Bg7 Qd5+ Ke8 Qh5+ Rf7
 11	 -0.97 	0:00.03	Re7 Qh5+ Kd8 Qh8 Ke8 Kc4 Rg7 e7 Rxe7 Kd4 Rg7 Qh5+ Kd8 Kd3 Re7 Kd2 Bg7 Qd5+ Ke8 Qg8+ Bf8 Qg4 Kd8 Qd1
 10	 -1.52 	0:00.03	Re7 Qh8 Rg7 Qh5+ Ke7 Qh2 Ke8 e7 Rxe7 Qh8 Rg7 Qh5+ Kd8 Qf5 Bc5 Qf6+ Re7
  9	 -3.15 	0:00.01	Rg8 Qh5+ Kd8 Qf7 Rg5+ Ke4 Be7 Qh7 Ke8 Qh8+ Bf8 Kf4 Rg7 Kf5 Rg1 Qe5
  8	 -3.20 	0:00.01	Rg1 Qf4 Rg7 Qf6 Re7 Ke4 Bg7 Qg6+ Kd8 Kf4 Bb2 Qb1
  7	 -3.37 	0:00.01	Rg8 Qf6 Rg7 Qe5 Kd8 Qh5 Re7 Ke5 Re8 Kf6 Be7+ Kg7
  6	 -3.75 	0:00.01	Rg1 Qf4 Rg7 Qf6 Re7 Qg6+ Kd8
  5	 -3.79 	0:00.01	Re7 Qg6+ Kd8 Ke5 Bg7+ Kf5 Bd4
  4	 -3.12 	0:00.01	Rg1 Qf4 Rd1+ Kc4 Bc5 Qf7+ Kd8
  3	 -3.45 	0:00.00	Rg1 Qh4 Rd1+ Ke4
  2	 -3.03 	0:00.00	Rg1 Qh5+ Kd8 Qf3
  1	 -3.17 	0:00.00	Rg1 Qh5+ Ke7
  0	#
Available here
https://github.com/MichaelB7/Stockfish/releases/tag/XI
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