Using dtz database: Is there a legal position that is resolved in 50 moves or positions are solved always with less than 50 move ? Do you have a link where there are examples with the max 50 moves rules position?
ciao & thanks you
50moverule and dtz
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niklasf
- Posts: 42
- Joined: Sat May 16, 2015 11:41 pm
Re: 50moverule and dtz
If I understand correctly what you are asking, there are many such positions. But they are not always easy to find. A good way to get these positions is:
1. Start with a long checkmate (http://kirill-kryukov.com/chess/longest ... ates.shtml has a list of examples)
2. It is probably a cursed win due to the 50 move rule. Use a DTZ tablebase and make some moves bringing it just over the edge.
3. Play out DTM vs. DTZ and hope that it is a draw. It might even be a draw if you play DTM vs. DTM as I show below.
As an example, I did this starting with the longest 6 piece endgame and got to this position.
[pgn][Event ""]
[Site ""]
[Date ""]
[Round ""]
[White ""]
[Black ""]
[Result ""]
[FEN "8/3R4/5N2/8/3nK3/4n3/3k4/8 b - - 0 1"]
[Setup "1"]
1... Nc2 2. Rd8 Ke2 3. Nd5 Nf3 4. Nf4+ Kf2 5. Re8 Nce1 6. Kf5 Kg3 7. Ne2+ Kf2 8.
Nc3 Nd3 9. Re2+ Kg3 10. Re3 { DTZ 86 but DTM optimal} ( 10. Ne4+ { DTZ 82} )
10... Ne1 11. Ne4+ Kh4 12. Ra3 Nd4+ 13. Ke5 Nc6+ 14. Kf4 Ng2+ 15. Kf5 Nd4+ 16.
Ke5 Nc6+ 17. Kd5 Nb4+ 18. Ke6 Nd3 19. Kf6 Ndf4 20. Ke5 Ne2 21. Ra2 Nef4 22. Ra8
Nh5 23. Rg8 Ne3 24. Nf2 Ng3 25. Rg6 Ne2 26. Ke4 Nf1 27. Rg4+ Kh5 28. Rg2 Kh4
29. Nd3 Nfg3+ 30. Ke3 Kh3 31. Rf2 Nc3 32. Rf8 Kh4 33. Kf3 Nge4 34. Kf4 Nf6 35.
Rh8+ Nh5+ 36. Kf5 Nd5 37. Ne5 Nf4 38. Nd7 Kg3 39. Nc5 Ng7+ 40. Kf6 Nfh5+ 41.
Kg6 Kf4 42. Rd8 Kf3 43. Rb8 Kf4 44. Rb1 Ke3 45. Rb4 Kf3 46. Nd7 Ke3 47. Ne5 Ke2
48. Rb3 Kd2 49. Ra3 Kc2 50. Nd7 Kb2 51. Rf3 Kc2 52. Nf6 Nf4+ 53. Rxf4 Ne6 54.
Re4 Nd8 55. Rb4 Kc3 56. Rb6 Kc2 57. Nd7 Kc3 58. Kf6 Kd3 59. Ke7 Kc3 60. Kxd8
Kd3 61. Rd6+ Ke3 62. Ke7 Kf3 63. Nf6 Ke3 64. Ke6 Ke2 65. Kf5 Kf3 66. Rd5 Ke3
67. Ng4+ Kf3 68. Rd2 Kg3 69. Rf2 Kh3 70. Kf4 Kh4 71. Rh2#[/pgn]
1. Start with a long checkmate (http://kirill-kryukov.com/chess/longest ... ates.shtml has a list of examples)
2. It is probably a cursed win due to the 50 move rule. Use a DTZ tablebase and make some moves bringing it just over the edge.
3. Play out DTM vs. DTZ and hope that it is a draw. It might even be a draw if you play DTM vs. DTM as I show below.
As an example, I did this starting with the longest 6 piece endgame and got to this position.
[pgn][Event ""]
[Site ""]
[Date ""]
[Round ""]
[White ""]
[Black ""]
[Result ""]
[FEN "8/3R4/5N2/8/3nK3/4n3/3k4/8 b - - 0 1"]
[Setup "1"]
1... Nc2 2. Rd8 Ke2 3. Nd5 Nf3 4. Nf4+ Kf2 5. Re8 Nce1 6. Kf5 Kg3 7. Ne2+ Kf2 8.
Nc3 Nd3 9. Re2+ Kg3 10. Re3 { DTZ 86 but DTM optimal} ( 10. Ne4+ { DTZ 82} )
10... Ne1 11. Ne4+ Kh4 12. Ra3 Nd4+ 13. Ke5 Nc6+ 14. Kf4 Ng2+ 15. Kf5 Nd4+ 16.
Ke5 Nc6+ 17. Kd5 Nb4+ 18. Ke6 Nd3 19. Kf6 Ndf4 20. Ke5 Ne2 21. Ra2 Nef4 22. Ra8
Nh5 23. Rg8 Ne3 24. Nf2 Ng3 25. Rg6 Ne2 26. Ke4 Nf1 27. Rg4+ Kh5 28. Rg2 Kh4
29. Nd3 Nfg3+ 30. Ke3 Kh3 31. Rf2 Nc3 32. Rf8 Kh4 33. Kf3 Nge4 34. Kf4 Nf6 35.
Rh8+ Nh5+ 36. Kf5 Nd5 37. Ne5 Nf4 38. Nd7 Kg3 39. Nc5 Ng7+ 40. Kf6 Nfh5+ 41.
Kg6 Kf4 42. Rd8 Kf3 43. Rb8 Kf4 44. Rb1 Ke3 45. Rb4 Kf3 46. Nd7 Ke3 47. Ne5 Ke2
48. Rb3 Kd2 49. Ra3 Kc2 50. Nd7 Kb2 51. Rf3 Kc2 52. Nf6 Nf4+ 53. Rxf4 Ne6 54.
Re4 Nd8 55. Rb4 Kc3 56. Rb6 Kc2 57. Nd7 Kc3 58. Kf6 Kd3 59. Ke7 Kc3 60. Kxd8
Kd3 61. Rd6+ Ke3 62. Ke7 Kf3 63. Nf6 Ke3 64. Ke6 Ke2 65. Kf5 Kf3 66. Rd5 Ke3
67. Ng4+ Kf3 68. Rd2 Kg3 69. Rf2 Kh3 70. Kf4 Kh4 71. Rh2#[/pgn]
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syzygy
- Posts: 5566
- Joined: Tue Feb 28, 2012 11:56 pm
Re: 50moverule and dtz
There are many positions that cannot be won within the 50-move rule, so there are also positions that are just on the edge (i.e. DTZ = 50 moves).acconcio wrote:Using dtz database: Is there a legal position that is resolved in 50 moves or positions are solved always with less than 50 move ? Do you have a link where there are examples with the max 50 moves rules position?
A few examples:
[D]8/8/8/8/8/8/k1K1B3/1q1B3B w - -
[D]8/8/8/5B2/8/2r5/8/BK1k1B2 w - -
[D]8/8/4B3/8/2B5/8/7N/1K1kq3 w - -
[D]8/B1r5/8/8/8/8/B7/1K1kN3 w - -
[D]n7/8/8/5k2/8/1PB5/8/K1B5 b - -
[D]8/3q3B/P7/K7/8/8/8/5k1B w - -
[D]7B/7B/P7/8/k7/8/4r3/K7 b - -
[D]8/8/8/p7/BB6/7n/8/K2k4 b - -
[D]8/1BP5/8/4q3/2KN4/8/4k3/8 b - -
[D]8/8/P3q3/1B6/8/N7/8/K2k4 w - -