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Subject: Re: Crafty move in endgame

Author: Michael Fuhrmann

Date: 00:32:39 03/08/02

Go up one level in this thread


On March 07, 2002 at 22:54:00, Robert Hyatt wrote:

>On March 07, 2002 at 22:00:56, Michael Fuhrmann wrote:
>
>>Crafty, playing without tablebases, likes the suicidal move Bxe3 in this
>>position. A flaw in its endgame knowledge?
>>
>>[D] 8/8/2k3P1/8/3b4/4R3/8/n4K2 b - - 0 56
>
>
>Do you have something broken?  Mine finds Bxe3 at ply=1, but at ply=2 it
>fails low to something winning for white and it changes to Kc5 and sticks
>with it forever...
>
>I can't reproduce Bxe3 beyond a 1 ply search and wouldn't expect to be able
>to do so as it is a trivial losing move that the search will pick up instantly.
>
>Which version?


latest version. here's log output from analysis, which I did after crafty played
the move in a game vs yace::


hash table memory = 24M bytes.
pawn hash table memory = 6M bytes.
threshold set to 6 pawns.


Crafty v18.13

White(1): analyze
              clearing hash tables
               book moves {e4, d4, c4, f4}
               book   0.0s      7%    c4! Nf6
in yc.fen
               book moves {e4, d4, c4, f4}
               book   0.0s     33%    d4! Nf6
8/8/2k3P1/8/3b4/4R3/8/n4K2 b - - 0 56

       +---+---+---+---+---+---+---+---+
    8  |   |   |   |   |   |   |   |   |
       +---+---+---+---+---+---+---+---+
    7  |   |   |   |   |   |   |   |   |
       +---+---+---+---+---+---+---+---+
    6  |   |   | *K|   |   |   | P |   |
       +---+---+---+---+---+---+---+---+
    5  |   |   |   |   |   |   |   |   |
       +---+---+---+---+---+---+---+---+
    4  |   |   |   | *B|   |   |   |   |
       +---+---+---+---+---+---+---+---+
    3  |   |   |   |   | R |   |   |   |
       +---+---+---+---+---+---+---+---+
    2  |   |   |   |   |   |   |   |   |
       +---+---+---+---+---+---+---+---+
    1  | *N|   |   |   |   | K |   |   |
       +---+---+---+---+---+---+---+---+
         a   b   c   d   e   f   g   h

end-game phase
              clearing hash tables
              time surplus   0.00  time limit 30.00 (3:30)
         nss  depth   time  score   variation (1)
                7     0.41     --   1. ... Nc2
                7     0.51   5.14   1. ... Nc2 2. Re4 Bg7 3. Rc4+ Kd5 4.
                                    Rxc2 Ke4 5. Kf2
                7     0.76   3.95   1. ... Kb7 2. g7 Bxg7 3. Re7+ Kc6 4.
                                    Rxg7 Kd6 5. Kf2 Nc2
                7     0.86   3.50   1. ... Kb5 2. Re7 Bc5 3. g7 Bxe7 4.
                                    g8=Q Kc5 5. Ke2
                7     0.90   3.30   1. ... Kc5 2. Re7 Kd6 3. g7 Kxe7 4.
                                    g8=Q Bb2 5. Kf2
                7->   0.97   3.30   1. ... Kc5 2. Re7 Kd6 3. g7 Kxe7 4.
                                    g8=Q Bb2 5. Kf2
                8     1.07   3.35   1. ... Kc5 2. Re7 Kd6 3. g7 Kxe7 4.
                                    g8=Q Bb2 5. Qh7+ Kd6 6. Kf2
                8->   1.38   3.35   1. ... Kc5 2. Re7 Kd6 3. g7 Kxe7 4.
                                    g8=Q Bb2 5. Qh7+ Kd6 6. Kf2
                9     1.47   3.35   1. ... Kc5 2. Re7 Kd6 3. g7 Kxe7 4.
                                    g8=Q Bb2 5. Qh7+ Kd6 6. Kf2 Bc3
                9->   1.86   3.35   1. ... Kc5 2. Re7 Kd6 3. g7 Kxe7 4.
                                    g8=Q Bb2 5. Qh7+ Kd6 6. Kf2 Bc3
               10     2.29     --   1. ... Kc5
               10     5.43   3.80   1. ... Kc5 2. Re7 Kd6 3. Rh7 Ke6 4.
                                    Rb7 Nc2 5. g7 Bxg7 6. Rxg7 Nb4
               10     7.18   3.55   1. ... Bxe3 2. g7 Bd4 3. g8=Q Kd6 4.
                                    Qd8+ Ke5 5. Ke2 Ke4 6. Qc8 Kd5 7. Kd3
               10->   7.79   3.55   1. ... Bxe3 2. g7 Bd4 3. g8=Q Kd6 4.
                                    Qd8+ Ke5 5. Ke2 Ke4 6. Qc8 Kd5 7. Kd3
               11     8.27   3.65   1. ... Bxe3 2. g7 Bd4 3. g8=Q Kd6 4.
                                    Ke2 Bf6 5. Kd3 Be5 6. Qb8+ Kd5 7. Qd8+
                                    Kc5 8. Ke4
               11->  10.19   3.65   1. ... Bxe3 2. g7 Bd4 3. g8=Q Kd6 4.
                                    Ke2 Bf6 5. Kd3 Be5 6. Qb8+ Kd5 7. Qd8+
                                    Kc5 8. Ke4
               12    10.83   3.65   1. ... Bxe3 2. g7 Bd4 3. g8=Q Kd6 4.
                                    Ke2 Bf6 5. Kd3 Be5 6. Qb8+ Kd5 7. Qd8+
                                    Kc5 8. Ke4 Bb2
               12->  13.32   3.65   1. ... Bxe3 2. g7 Bd4 3. g8=Q Kd6 4.
                                    Ke2 Bf6 5. Kd3 Be5 6. Qb8+ Kd5 7. Qd8+
                                    Kc5 8. Ke4 Bb2
               13    16.13   3.65   1. ... Bxe3 2. g7 Bd4 3. g8=Q Kc5 4.
                                    Qd8 Kc4 5. Ke2 Be5 6. Qd3+ Kc5 7. Ke3
                                    Bb2 8. Qf5+ Kc4 9. Ke4
               13->  20.40   3.65   1. ... Bxe3 2. g7 Bd4 3. g8=Q Kc5 4.
                                    Qd8 Kc4 5. Ke2 Be5 6. Qd3+ Kc5 7. Ke3
                                    Bb2 8. Qf5+ Kc4 9. Ke4
               14    31.98     --   1. ... Bxe3
               14    37.96   4.08   1. ... Bxe3 2. g7 Bd4 3. g8=Q Kc5 4.
                                    Ke2 Kb4 5. Kd3 Nb3 6. Qc4+ Ka3 7. Kc2
                                    Na1+ 8. Kb1 Nb3 9. Qb5 Nd2+ 10. Kc2
               14->   1:57   4.08   1. ... Bxe3 2. g7 Bd4 3. g8=Q Kc5 4.
                                    Ke2 Kb4 5. Kd3 Nb3 6. Qc4+ Ka3 7. Kc2
                                    Na1+ 8. Kb1 Nb3 9. Qb5 Nd2+ 10. Kc2
               15     2:08   4.08   1. ... Bxe3 2. g7 Bd4 3. g8=Q Kc5 4.
                                    Ke2 Kb4 5. Kd3 Nb3 6. Qc4+ Ka3 7. Kc2
                                    Na1+ 8. Kb1 Nb3 9. Qb5 Nd2+ 10. Kc2
                                    Nf3
               15->   2:35   4.08   1. ... Bxe3 2. g7 Bd4 3. g8=Q Kc5 4.
                                    Ke2 Kb4 5. Kd3 Nb3 6. Qc4+ Ka3 7. Kc2
                                    Na1+ 8. Kb1 Nb3 9. Qb5 Nd2+ 10. Kc2
                                    Nf3
               16     3:43     --   1. ... Bxe3
Black(0): quit
execution complete.



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