Author: blass uri
Date: 06:40:53 06/21/00
Go up one level in this thread
On June 21, 2000 at 08:30:59, Enrique Irazoqui wrote:
>[D]1r6/1pb1k1p1/4p2p/1p1p4/3Pp2P/1R2P1PB/1P2P1K1/8 b - - 0 1
>
>Yesterday I looked at this position that reveals once again how much trouble
>programs have in recognizing the importance of blocked pieces. Some programs
>pick and drop 1...b4, but none of them realize that the blocked rook is out of
>the game until the search makes them see the consequences many hours later. The
>evaluation at the initial position or after 1...b4 2.Rxb4 b5 3.Rb3 b4 is almost
>the same. It takes 61 minutes for F6a and 335 minutes for Tiger to pick b4, and
>much, much longer to fail high.
>
>[Event "Biel"]
>[Site "?"]
>[Date "1977.??.??"]
>[Round "?"]
>[White "Andersson"]
>[Black "Torre"]
>[Result "0-1"]
>[SetUp "1"]
>[FEN "1r6/1pb1k1p1/4p2p/1p1p4/3Pp2P/1R2P1PB/1P2P1K1/8 b - - 0 1"]
>[PlyCount "7"]
>[EventDate "1997.??.??"]
>
>1... b4 $3 2. Rxb4 b5 $1 3. h5 (3. Rb3 b4 {
>/\...Bd6, Re8 (>< e6), Kd8-c7-...-c4 -+; >< g3}) 3... Bd6 4. Rb3 b4 $1 $19 {
>>< Rb3, g3; /\ 5...Re8 (>< e6), 6... Kd8-c7-...-c4 -+ Andersson-Torre/Biel1977}
>0-1
>
>n-Torre/Biel1977}
>0-1
>
>The same theme appears in the Scherbakov-Rebel game:
>
>[D]3r4/p3kp2/2p1ppbp/2b5/P3P3/2NB1P2/1PK3PP/7R b - - 0 21
>
>Here Rebel played e5??, the bishop became a big pawn and black lost. Again, all
>the programs I tried gave a similar evaluation to this initial position and
>after 23.h3, failing to realize that in practice black is a piece down.
>
>[Event "Monthly GM Challenge"]
>[Site "?"]
>[Date "2000.??.??"]
>[Round "7"]
>[White "Scherbakov, R."]
>[Black "Comp Rebel Century"]
>[Result "1-0"]
>[WhiteElo "2540"]
>[BlackElo "2500"]
>[Annotator "Scherbakov,R"]
>[SetUp "1"]
>[FEN "3r4/p3kp2/2p1ppbp/2b5/P3P3/2NB1P2/1PK3PP/7R b - - 0 21"]
>[PlyCount "70"]
>[EventDate "2000.??.??"]
>
>21... e5 $4 {Unbelievable!!! Obviously Rebel did not consider seriously
>White's next move after which Black is practically a piece down.} (21... f5 $5
>{It was better to make almost any other move (or even don't move on the whole!)
>. Still was not so bad as after direct} 22. exf5 Bxf5 23. Bxf5 exf5 {
>Black has active pieces and good play on the kingside.}) 22. g4 $1 {The Bishop
>on g6 is now a "big pawn". The attempt to escape with f6-f5 is pointless.}
>22... h5 23. h3
>
>[D]8/4k3/4bpp1/7p/1p2p3/4P1PB/1P2P1KP/8 b - - 0 1
>
>Time ago I posted this one, which is another case of blindness regarding blocked
>pieces. Here, a few programs pick the winning f5, but the difference in
>evaluation between f5 and next best is insignificant.
>
>[Event "Black to move f5"]
>[Site "?"]
>[Date "1997.??.??"]
>[Round "?"]
>[White "Blocking bishop"]
>[Black "?"]
>[Result "0-1"]
>[SetUp "1"]
>[FEN "8/4k3/4bpp1/7p/1p2p3/4P1PB/1P2P1KP/8 b - - 0 1"]
>[PlyCount "1"]
>[EventDate "1997.??.??"]
>
>1... f5 0-1
>
>[D]r4rk1/p1q2ppp/1pn2n2/2p1p3/3PP1b1/P1P2N2/B4PPP/R1BQR1K1 w - - 0 14
>
>Another position I posted bbefore. No program plays dxc5, invariably picking d5
>instead and blocking their own bishop on a2.
>
>[Event "Linares14th"]
>[Site "Linares"]
>[Date "1997.??.??"]
>[Round "11"]
>[White "Kasparov, Gary"]
>[Black "Kramnik, Vladimir"]
>[Result "1-0"]
>[WhiteElo "2795"]
>[BlackElo "2740"]
>[Annotator "Psakhis"]
>[SetUp "1"]
>[FEN "r4rk1/p1q2ppp/1pn2n2/2p1p3/3PP1b1/P1P2N2/B4PPP/R1BQR1K1 w - - 0 14"]
>[PlyCount "87"]
>[EventDate "1997.02.16"]
>[Source "ChessBase"]
>[SourceDate "1997.04.10"]
>
>14. dxc5 $1 {Natural 14.d5 will be serious positional mistake- bishop on a2
> could be closed for a long time (Psakhis).}
>
>There is a pattern in the first three positions that has to do with a piece
>being blocked for as long as the opponent wants to, which effectively means
>losing a piece and the game. No program sees it. Unless they find by search they
>have no clue, and search often takes too long. Is it that difficult to teach
>programs about all this?
>
>Enrique
I am interested to know if you tried to check if chess system tal knows about
it(I have not this program so I cannot check it).
I know that chess system tal has big positional scores so I suspect that it may
understand these positions better.
Uri
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