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Subject: Re: How many programs select the correct move Bb6! trapping the knight !

Author: Mike Byrne

Date: 14:49:20 05/30/03

Go up one level in this thread


On May 30, 2003 at 08:57:45, Jorge Pichard wrote:

>With White to move Ruffian selected Bf2? against Aristarch 4.21 and now the
>knight can escape easy.
>
>[D]8/8/8/4B1k1/4K3/8/4B1n1/8 w - -

Bf2? --not possible ,maybe Bf1 and there is no escape

White(1): Bf1
              time used:   2:11
end-game phase
              clearing hash tables
              time surplus   0.00  time limit 22.50 (3:30)
              depth   time  score   variation (1)
starting thread 1
                2     0.00  Mat16   1. ... Ne1 <EGTB>
                2     0.00  Mat36   1. ... Nh4 <EGTB>
                2->   0.04  Mat36   1. ... Nh4 <EGTB>
                3     0.04  Mat36   1. ... Nh4 <EGTB>
                3->   0.04  Mat36   1. ... Nh4 <EGTB>
                4     0.04  Mat36   1. ... Nh4 <EGTB>
                4->   0.04  Mat36   1. ... Nh4 <EGTB>
              time=0.04  cpu=75%  mat=3  n=72  fh=100%  nps=10k
              ext-> chk=0 cap=0 pp=0 1rep=0 mate=0
              predicted=0  nodes=72  evals=1
              endgame tablebase-> probes done=9  successful=9
              SMP->  split=3  stop=0  data=2/32  cpu=0.03  elap=0.04

mated in 36 moves.

kibitz mated in 36 moves.

if Bg7 , it' still mate - just takes longer

White(1): Bg7
              time used:   3:54
              time surplus   0.00  time limit 22.49 (3:29)
              depth   time  score   variation (1)
                2     0.00  Mat35   1. ... Nh4 <EGTB>
                2     0.00  Mat42   1. ... Nf4 <EGTB>
                2->   0.00  Mat42   1. ... Nf4 <EGTB>
                3     0.00  Mat42   1. ... Nf4 <EGTB>
                3->   0.00  Mat42   1. ... Nf4 <EGTB>
                4     0.00  Mat42   1. ... Nf4 <EGTB>
                4->   0.01  Mat42   1. ... Nf4 <EGTB>
              time=0.01  cpu=0%  mat=3  n=40  fh=100%  nps=10k
              ext-> chk=0 cap=0 pp=0 1rep=0 mate=0
              predicted=0  nodes=40  evals=1
              endgame tablebase-> probes done=6  successful=6
              SMP->  split=4  stop=0  data=2/32  cpu=0.00  elap=0.01

mated in 42 moves.

kibitz mated in 42 moves.

Many of the modern programs that do not have EGTB will not play this correctly,
as the programmer lets the EGTB so the work for it.   A program such as Crafty,
which has large portion of code written before  EGTB will play an ending like
this correctly with EGTB


analysis w/o egtb 4.7 seconds to see optimal move Bc7

Crafty v19.3 (2 cpus)

White(1): 8/8/8/4B1k1/4K3/8/4B1n1/8 w - -
White(1):
White(1): st 9999
search time set to 9999.00.
White(1): go
end-game phase
              clearing hash tables
              time surplus   0.00  time limit 166:39 (166:39)
              depth   time  score   variation (1)
starting thread 1
                4     0.02   1.26   1. Bh8 Ne1 2. Bg7 Nc2
                4->   0.02   1.26   1. Bh8 Ne1 2. Bg7 Nc2
                5     0.02   1.26   1. Bh8 Ne1 2. Bg7 Nc2 3. Ba6
                5->   0.02   1.26   1. Bh8 Ne1 2. Bg7 Nc2 3. Ba6
                6     0.02   1.26   1. Bh8 Ne1 2. Bg7 Nc2 3. Ba6 Kg4
                6->   0.03   1.26   1. Bh8 Ne1 2. Bg7 Nc2 3. Ba6 Kg4
                7     0.03   1.26   1. Bh8 Nf4 2. Ba6 Ng2 3. Ke5 Ne1 4.
                                    Be2
                7->   0.05   1.26   1. Bh8 Nf4 2. Ba6 Ng2 3. Ke5 Ne1 4.
                                    Be2
                8     0.05   1.26   1. Bh8 Nf4 2. Ba6 Ng2 3. Ke5 Nf4 4.
                                    Bf6+ Kg4 5. Bc4
                8     0.05   1.28   1. Bf1 Nh4 2. Bc7 Ng6 3. Bd8+ Kg4 4.
                                    Be2+ Kg3 5. Bf3 Kf2
                8->   0.08   1.28   1. Bf1 Nh4 2. Bc7 Ng6 3. Bd8+ Kg4 4.
                                    Be2+ Kg3 5. Bf3 Kf2 (s=3)
                9     0.08   1.28   1. Bf1 Nh4 2. Bc7 Ng6 3. Bd8+ Kg4 4.
                                    Be2+ Kg3 5. Bf3 Kf2 6. Bg4 (s=2)
                9->   0.13   1.28   1. Bf1 Nh4 2. Bc7 Ng6 3. Bd8+ Kg4 4.
                                    Be2+ Kg3 5. Bf3 Kf2 6. Bg4 (s=16)
               10     0.14   1.28   1. Bf1 Nh4 2. Bc7 Ng6 3. Bd8+ Kg4 4.
                                    Be2+ Kg3 5. Bf3 Kf2 6. Bg4 Kg3 (s=15)
               10->   0.35   1.28   1. Bf1 Nh4 2. Bc7 Ng6 3. Bd8+ Kg4 4.
                                    Be2+ Kg3 5. Bf3 Kf2 6. Bg4 Kg3 (s=16)
               11     0.39   1.28   1. Bf1 Nh4 2. Bc7 Kg6 3. Bd8 Nf5 4.
                                    Bd3 Nh6 5. Ke5+ Kf7 6. Be2 Kg6 (s=15)
               11->   0.80   1.28   1. Bf1 Nh4 2. Bc7 Kg6 3. Bd8 Nf5 4.
                                    Bd3 Nh6 5. Ke5+ Kf7 6. Be2 Kg6 (s=9)
               12     0.89   1.28   1. Bf1 Nh4 2. Bc7 Kg6 3. Bd8 Nf5 4.
                                    Bd3 <HT> (s=8)
               12->   2.25   1.28   1. Bf1 Nh4 2. Bc7 Kg6 3. Bd8 Nf5 4.
                                    Bd3 Nh6 <HT> (s=11)
               13     2.47   1.28   1. Bf1 Nh4 2. Bc7 Kg6 3. Bd8 Nf5 4.
                                    Bd3 Nh6 5. Be7 Kg7 6. Ke5 Kf7 7. Bd8
                                    (s=10)
               13     4.67     ++   1. Bc7!!
               13->   6.63   1.67   1. Bc7
               14     7.44     ++   1. Bc7!!
               14     8.66   7.90   1. Bc7 Kh6 2. Bd8 Ne1 3. Ba5 Ng2 4.
                                    Bd2+ Kg6 5. Kf3 Nh4+ 6. Kg4 Kf7 7.
                                    Kxh4 Ke6 8. Bc4+ Kd6 9. Kg5
               14->  13.60   7.90   1. Bc7 Kh6 2. Bd8 Ne1 3. Ba5 Ng2 4.
                                    Bd2+ Kg6 5. Kf3 Nh4+ 6. Kg4 Kf7 7.
                                    Kxh4 Ke6 8. Bc4+ Kd6 9. Kg5 (s=5)
               15    16.78   7.90   1. Bc7 Kh6 2. Bd8 Ne1 3. Ba5 Ng2 4.
                                    Bd2+ Kg6 5. Kf3 Kf5 6. Kxg2 Ke4 7.
                                    Bf1 Kd4 8. Kf3 Kc5 (s=4)
?              15    29.27  26/26*  1. Bh5
White(1): ?
              time=29.52  cpu=196%  mat=3  n=62496043  fh=93%  nps=2117k
              ext-> chk=2845908 cap=51497 pp=0 1rep=16098 mate=977
              predicted=0  nodes=62496043  evals=1
              endgame tablebase-> probes done=0  successful=0
              SMP->  split=1399  stop=111  data=7/32  cpu=57.90  elap=29.52

White(1): Bc7
              time used:  29.52



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