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Subject: Re: THE move to achieve a draw is Nd8

Author: Paulo Soares

Date: 11:15:44 07/20/00

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On July 20, 2000 at 01:02:39, Dann Corbit wrote:

>On July 19, 2000 at 09:33:55, Andrew Williams wrote:
>
>>Here is a position that arose in a game on ICC today (PGN below):
>>
>>[D] 8/1N6/6p1/2K1k2p/8/1PP5/8/8 w - -  acd 11; acn 576768; acs 5; ce 772; fmvn
>>60; hmvc 0; id "PostModernist vs Tinker"; pm Kc6 ; pv 60. Kc6 h4 61. Nc5 Kf4 62.
>>Kd5
>
>Intersting that according to crafty, neither of the obvious moves (Nd6, Kc4)
>have a good outcome.  In order to achieve the draw, Nd8 is necessary and it is
>very, very deep to find it [48 minutes on a PII 350 MHz to find it!].  I think
>this might be a good test position for deep searching ability.
>
>How do commercial engines do on this one?
>
>choose from book moves randomly (using weights.)
>choose from 5 best moves.
>book learning enabled
>result learning enabled
>position learning enabled
>threshold set to 9 pawns.
>4 piece tablebase files found
>1302kb of RAM used for TB indices and decompression tables
>
>Crafty v17.11
>
>White(1): st 9999
>search time set to 9999.00.
>White(1): epdpfga epd.epd epd.out
>PFGA: EPD record: 1
>end-game phase
>              clearing hash tables
>              time surplus   0.00  time limit 166:39 (166:39)
>         nss  depth   time  score   variation (1)
>                9     0.84   3.60   1. Nd6 h4 2. Nc4+ Ke4 3. b4 h3 4. Nd2+
>                                    Kf4 5. Nf1 g5 6. Nh2
>                9->   1.05   3.60   1. Nd6 h4 2. Nc4+ Ke4 3. b4 h3 4. Nd2+
>                                    Kf4 5. Nf1 g5 6. Nh2
>               10     1.66   3.21   1. Nd6 h4 2. Nc4+ Kf4 3. Nd2 h3 4.
>                                    Nf1 g5 5. Kd5 g4 6. Nh2
>               10->   2.23   3.21   1. Nd6 h4 2. Nc4+ Kf4 3. Nd2 h3 4.
>                                    Nf1 g5 5. Kd5 g4 6. Nh2
>               11     2.75   3.25   1. Nd6 h4 2. Nc4+ Kf4 3. Nd2 h3 4.
>                                    Nf1 g5 5. b4 g4 6. b5 Ke5
>               11     4.48   3.47   1. Kc6 g5 2. Nc5 g4 3. Nd7+ Kf4 4.
>                                    Nf6 h4 5. Nd5+ Ke4 6. b4 h3 7. b5
>               11->   5.19   3.47   1. Kc6 g5 2. Nc5 g4 3. Nd7+ Kf4 4.
>                                    Nf6 h4 5. Nd5+ Ke4 6. b4 h3 7. b5
>               12     8.40     --   1. Kc6
>               12     9.94   2.78   1. Kc6 h4 2. Nc5 Kf4 3. Kd5 h3 4. Ne4
>                                    h2 5. Nf2 g5 6. c4 g4 7. c5
>               12    10.16     ++   1. Nd6!!
>               12->  13.42   3.17   1. Nd6
>               13    15.22     --   1. Nd6
>               13    17.63   0.65   1. Nd6 h4 2. Nc4+ Kf4 3. Nd2 h3 4.
>                                    Nf1 g5 5. b4 g4 6. b5 g3 7. Nxg3 Kxg3
>               13    18.10     ++   1. Kc6!!
>               13    26.95   1.29   1. Kc6 g5 2. Kb5 g4 3. Nd8 g3 4. Nc6+
>                                    Ke4 5. Nd4 g2 6. Ne2 Kd3 7. Ng1 Kxc3
>                                    8. b4
>               13    29.39     ++   1. Kc4!!
>               13    30.17   3.08   1. Kc4 h4 2. Nc5 h3 3. Nd3+ Kd6 4.
>                                    Nf2 h2 5. b4 Kc6 6. Nh1 g5 7. Kd4 g4
>                                    8. c4
>               13->  31.00   3.08   1. Kc4 h4 2. Nc5 h3 3. Nd3+ Kd6 4.
>                                    Nf2 h2 5. b4 Kc6 6. Nh1 g5 7. Kd4 g4
>                                    8. c4
>               14    43.15   3.17   1. Kc4 g5 2. Nc5 g4 3. Kd3 h4 4. Ke3
>                                    h3 5. Ne4 Kf5 6. Ng3+ Ke5 7. Nf1 Kd5
>                                    8. Ng3
>               14->  50.36   3.17   1. Kc4 g5 2. Nc5 g4 3. Kd3 h4 4. Ke3
>                                    h3 5. Ne4 Kf5 6. Ng3+ Ke5 7. Nf1 Kd5
>                                    8. Ng3
>               15     1:08   3.19   1. Kc4 h4 2. Nc5 Kf4 3. Kd3 g5 4. Ke2
>                                    g4 5. Nd3+ Kf5 6. Kf2 Ke4 7. c4 h3
>                                    8. Kg3 Kf5
>               15->   1:22   3.19   1. Kc4 h4 2. Nc5 Kf4 3. Kd3 g5 4. Ke2
>                                    g4 5. Nd3+ Kf5 6. Kf2 Ke4 7. c4 h3
>                                    8. Kg3 Kf5
>               16     1:32   3.25   1. Kc4 h4 2. Nc5 Kf4 3. Kd3 g5 4. Ke2
>                                    g4 5. Nd3+ Ke4 6. Nf2+ Kf5 7. b4 g3
>                                    8. Nh3 Ke6 9. b5 Kd5
>               16->   1:56   3.25   1. Kc4 h4 2. Nc5 Kf4 3. Kd3 g5 4. Ke2
>                                    g4 5. Nd3+ Ke4 6. Nf2+ Kf5 7. b4 g3
>                                    8. Nh3 Ke6 9. b5 Kd5
>               17     2:12   3.48   1. Kc4 h4 2. Nc5 Kf4 3. Kd3 g5 4. Ke2
>                                    g4 5. Nd3+ Kf5 6. Kf2 Ke4 7. c4 g3+
>                                    8. Kg2 Kd4 9. c5 Kd5 10. b4
>               17->   2:57   3.48   1. Kc4 h4 2. Nc5 Kf4 3. Kd3 g5 4. Ke2
>                                    g4 5. Nd3+ Kf5 6. Kf2 Ke4 7. c4 g3+
>                                    8. Kg2 Kd4 9. c5 Kd5 10. b4
>               18     3:28     ++   1. Kc4!!
>               18     5:57   4.12   1. Kc4 h4 2. Nc5 Kf4 3. Kd3 g5 4. b4
>                                    Kf3 5. Ne4 g4 6. Nd2+ Kf4 7. b5 h3
>                                    8. b6 h2 9. b7 h1=Q 10. b8=Q+ Kf5 11.
>                                    Qf8+ Ke5 12. c4
>               18->   7:40   4.12   1. Kc4 h4 2. Nc5 Kf4 3. Kd3 g5 4. b4
>                                    Kf3 5. Ne4 g4 6. Nd2+ Kf4 7. b5 h3
>                                    8. b6 h2 9. b7 h1=Q 10. b8=Q+ Kf5 11.
>                                    Qf8+ Ke5 12. c4
>               19     9:03     --   1. Kc4
>               19    11:04   3.53   1. Kc4 h4 2. Nc5 Kf4 3. Kd3 h3 4. Ke2
>                                    h2 5. Nd3+ Kg3 6. Nf2 g5 7. c4 g4 8.
>                                    Ke3 Kh4 9. Nh1 Kg5 10. c5 Kf5 11. c6
>               19->  15:58   3.53   1. Kc4 h4 2. Nc5 Kf4 3. Kd3 h3 4. Ke2
>                                    h2 5. Nd3+ Kg3 6. Nf2 g5 7. c4 g4 8.
>                                    Ke3 Kh4 9. Nh1 Kg5 10. c5 Kf5 11. c6
>               20    16:54     --   1. Kc4
>               20    24:36  -1.12   1. Kc4 h4 2. Nc5 Kf4 3. Kd3 h3 4. Ke2
>                                    h2 5. Nd3+ Kg3 6. Nf2 Kg2 7. b4 g5
>                                    8. b5 g4 9. b6 g3 10. Nh1 Kxh1 11.
>                                    b7 g2 12. b8=Q g1=Q
>               20    40:55     ++   1. Nd8!!
>               20    79:15   0.00   1. Nd8 h4 2. Nc6+ Ke4 3. b4 h3 4. b5
>                                    h2 5. b6 h1=Q 6. b7 Qc1 7. b8=Q Qxc3+
>                                    8. Kd6 Qg3+ 9. Ke7 Qxb8 10. Nxb8 <HT>
>               20->  81:01   0.00   1. Nd8 h4 2. Nc6+ Ke4 3. b4 h3 4. b5
>                                    h2 5. b6 h1=Q 6. b7 Qc1 7. b8=Q Qxc3+
>                                    8. Kd6 Qg3+ 9. Ke7 Qxb8 10. Nxb8 <HT>
>               21    84:50   0.00   1. Nd8 h4 2. Nc6+ Ke4 3. b4 h3 4. b5
>                                    h2 5. b6 h1=Q 6. b7 Qc1 7. b8=Q Qxc3+
>                                    8. Kd6 Qg3+ 9. Ke7 Qxb8 10. Nxb8 <HT>
>               21-> 109:53   0.00   1. Nd8 h4 2. Nc6+ Ke4 3. b4 h3 4. b5
>                                    h2 5. b6 h1=Q 6. b7 Qc1 7. b8=Q Qxc3+
>                                    8. Kd6 Qg3+ 9. Ke7 Qxb8 10. Nxb8 <HT>
>               22   119:32   0.00   1. Nd8 h4 2. Nc6+ Ke4 3. b4 h3 4. b5
>                                    h2 5. b6 h1=Q 6. b7 Qc1 7. b8=Q Qxc3+
>                                    8. Kd6 Qg3+ 9. Ke7 Qxb8 10. Nxb8 <HT>
>               22-> 144:37   0.00   1. Nd8 h4 2. Nc6+ Ke4 3. b4 h3 4. b5
>                                    h2 5. b6 h1=Q 6. b7 Qc1 7. b8=Q Qxc3+
>                                    8. Kd6 Qg3+ 9. Ke7 Qxb8 10. Nxb8 <HT>
>              time=166:39  cpu=99%  mat=3  n=2470367590  fh=3%  nps=247041
>              ext-> checks=218881087 recaps=5807422 pawns=9901037 1rep=3817901
>thrt:56281
>              predicted=0  nodes=2470367590  evals=438265661
>              endgame tablebase-> probes done=85362  successful=85362
>              hashing-> trans/ref=1%  pawn=0%  used=99%
>White(1): quit

Following the best moves analyzed by the programs, I arrived to the following
line:
1. Kc4 h4 2. Nc5 Kf4 3. Kd3 h3 4. Ke2 h2 5. Nd3+ Kg3 6. Nf2 Kg2 7. b4 g5 8. b5
g4 9. b6 g3 10. Nh1 Kxh1 11. b7 g2 12. b8=Q g1=Q 13. Qf4

The diagram below shows the position after 13. Qf4.
Isn't this position a draw?

[D] 8/8/8/8/5Q2/2P5/4K2p/6qk b - - 0 13

Paulo Soares, from Brazil



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