Author: Anthony Cozzie
Date: 14:36:54 06/26/03
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On June 26, 2003 at 11:18:26, Igor Gorelikov wrote: >One Test position >================== > >There is a section of everyday's puzzles on my site: >http://www.digichess.gr/infiniteloop/home.php > >All puzzles are taken from engine to engine games of Infinite Loop. > >Prior to publish a puzzle on my site I always offer Crafty 19.3 to solve it. > >I was amazed that today's puzzle was hard to solve even for Crafty so it >can be a good test position for any chess engine. > >What Phalanx XXII (engine number 10 among free WB engines) plays here as >white (and find it at once)? > >[D] r1bq3r/ppp3pp/3k4/3p4/3nP1Q1/8/PP4PP/RN3RK1 w - - 0 17 > >PS: Yace can find it after some time too. > >Best regards, >Igor Gorelikov Zappa waffles back and forth between Qg3 and e5, both of which win the Knight on d4, at which point white is a pawn down, but has compensation. Most programs should display something between 0-1 depending on how much positional compensation they give white for the pawn. 1. e5 Kc5 2. Rc1 Kb6 = (-0.66) Depth: 2 00:00:00.00 1kN 1. Qg3 Kc6 2. Qc3 Kd7 3. Qxd4 = (-0.67) Depth: 3 00:00:00.02 3kN 1. Qg3 Kc6 2. Qc3 Kd6 3. Qxd4 Kc6 + (-0.37) Depth: 4 00:00:00.03 4kN 1. Qg3 Kc6 2. Qc3 Kb6 3. Qxd4 c5 4. Qxd5 = (-0.09) Depth: 4 00:00:00.11 15kN 1. e5 Kxe5 2. Qxg7 Kd6 3. Qxd4 c5 4. Rf6 Be6 = (0.02) Depth: 5 00:00:00.40 56kN 1. Qg3 Kc6 2. Qc3 Kb6 3. Qxd4 c5 4. Qxd5 Qxd5 5. exd5 = (-0.09) Depth: 6 00:00:01.41 209kN 1. e5 Kxe5 2. Qxg7 Kd6 3. Qxd4 Rf8 4. Rxf8 Qxf8 5. Nc3 = (-0.06) Depth: 7 00:00:04.00 657kN 1. e5 Kxe5 2. Qf4 Ke6 3. Re1 Kd7 4. Qxd4 Qg8 5. Qg4 Kd6 6. Qf4 Kd7 7. Qg4 = (0.00) Depth: 8 00:00:11.73 2225kN 1. e5 Kxe5 2. Qxg7 Kd6 3. Qxd4 c6 4. Rf6 Be6 5. Qb4 c5 6. Qf4 Kd7 = (0.00) Depth: 9 00:00:48.38 9935kN 1. e5 Kxe5 2. Qxg7 Kd6 3. Qxd4 c6 4. Nc3 Be6 5. Ne4 Kc7 6. Qe5 Kb6 7. Qxe6 dxe4 = (0.10) Depth: 10 00:02:02.66 25877kN 1. e5 Kxe5 2. Qxg7 Kd6 3. Qxd4 c6 4. Nc3 Be6 5. Ne4 Kc7 6. Qe5 Kb6 7. b4 Qe7 8. Nc5 = (0.20) Depth: 11 00:06:20.15 79555kN 1. e5 Kxe5 2. Qxg7 Kd6 3. Qxd4 Be6 4. Nc3 c6 5. Ne4 = (0.20) Depth: 12 00:37:22.37 475610kN 1. e5 Kxe5 2. Qf4 Ke6 3. Qxd4 c6 4. Qxg7 Kd6 5. Nc3 Qb6 6. Kh1 Re8 7. Qg3 Kd7 8. Rae1 Rxe1 9. Rxe1 = (0.44) Depth: 13 01:23:55.07 1082116kN Actually seeing the win is pretty hard for Zappa. Even after 1. e5 Kxe5 2. Qxg7 Kd6 3. Qxd4 it takes some time to give a decisive advantage to white: 1...Be6 2. Nc3 Kd7 3. Rae1 Re8 4. Nxd5 Kc8 5. Qe4 Bxd5 6. Qxe8 Bxa2 7. Qxd8 Kxd8 8. Kf2 - (-0.90) Depth: 12 00:04:24.75 59964kN 1...Be6 2. Nc3 Kd7 3. Rae1 Re8 4. Nxd5 Kc8 5. Qe4 c6 6. Nf6 Qb6 7. Rf2 Re7 = (-1.15) Depth: 12 00:09:29.95 131233kN 1...Be6 2. Nc3 Kd7 3. Rae1 Re8 4. Nxd5 Kc8 5. Qe5 Kb8 6. Nf6 Re7 7. Nxh7 Qd2 = (-0.99) Depth: 13 00:15:03.63 208272kN 1...Be6 2. Nc3 Kd7 3. Rae1 Re8 4. Ne4 Kc8 5. Nf6 Re7 6. Rxe6 c6 7. Rxe7 Qxe7 8. Nxd5 - (-1.29) Depth: 14 00:36:43.44 517283kN (Meaning that the position is at least 1.29 pawns in favor of white) If Zappa needs a 14 ply search to determine a decisive win for white, it means that at the root position it would need a 17 ply search (e5 and Qxg7 are checks) which would probably require a day at least. Since Zappa would play the correct moves anyway, I'm not to worried. Anthony
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