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tromp / ChessPositionRanking

Software suite for ranking chess positions and accurately estimating the number of legal chess positions
MIT License
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k3NQ2/2rp3R/3K1BQp/2r2N2/r2pQPq1/n2N3r/np2b1PB/1BR1b3 b - - 0 1 #688

Closed tromp closed 3 years ago

tromp commented 3 years ago

k3NQ2/2rp3R/3K1BQp/2r2N2/r2pQPq1/n2N3r/np2b1PB/1BR1b3 b - - 0 1

img

Single Check wx 2 wp 2 wpr 4 wpx 2 maxuwp 2 minopp 0 bx 2 bp 4 bpr 2 bpx 2 maxubp 4 minopp 0

rooklift commented 3 years ago

Hi, what's your definition of proof? I got this position but exceeded the 50 move rule slightly.

1. b3 a5 2. b4 axb4 3. a4 b3 4. a5 b2 5. Nc3 b1=R 6. a6 Nc6 7. a7 Rb8 8. a8=Q
Rb6 9. Qa2 Ra6 10. Qb1 Raa8 11. d4 Na7 12. Na2 c5 13. c4 cxd4 14. c5 b5 15. c6
b4 16. c7 Ba6 17. c8=Q b3 18. Qc8c2 b2 19. e4 f5 20. exf5 e5 21. f6 Bd6 22. f7+
Ke7 23. f8=B+ Ke8 24. Be7 Bc7 25. Bh4 g5 26. Bg3 h6 27. h4 Nf6 28. hxg5 Nd5 29.
g6 Nb4 30. g7 Rf8 31. g8=N e4 32. Qa4 e3 33. Bd3 e2 34. Kd2 e1=R 35. f4 Qe7 36.
Bh4 Kd8 37. Bf6 Kc8 38. Qb1c2 Rb5 39. Qab3 Ra5 40. Qd5 Ra4 41. Qcc6 Kb8 42. Bg5
Re3 43. Nf6 Rh3 44. Ne8 Rf5 45. Qe4 Rc5 46. Bh4 Ba5 47. Ke2 Nb5 48. Qc2 Ra7 49.
Bg3 Nc7 50. Kf3 Qg5 51. Qed5 Bc4 52. Ke4 Qh4 53. Ke5 Qg4 54. Kd6 Nb5+ 55. Ke7
Na3 56. Kd6 Rc7 57. Qe2 Bb5 58. Bb1 Bd3 59. Qe7 Be2 60. Qf8 Nd3 61. Be3 Nc1 62.
Nc3 Na2 63. Bc2 Bb4 64. Ne4 Be1 65. Rc1 Rb7 66. Bb1 Rc7 67. Bh2 Rb7 68. Nf3 Bf2
69. Ne1 Bg1 70. Nd3 Rc7 71. Bf2 Rb7 72. Bh4 Rc7 73. Bf6 Rb7 74. Qg5 Rc7 75. Qg6
Rb7 76. Ng3 Rc7 77. Nf5 Rb7 78. Qf3 Bf2 79. Qe3 Be1 80. Rf1 Qh4 81. Rf3 Qg4 82.
Rg3 Qh4 83. Rg5 Qg4 84. Qgf7 Rbc7 85. Rg7 Rb7 86. Rh7 Rbc7 87. Qg6 Ka8 88. Qe4+
1/2-1/2
tromp commented 3 years ago

The 50 move rule doesn't apply since you moved pawns and made captures frequently. Your PGN notation is accepted by https://lichess.org/analysis where I verified the final FEN, so that definitely falls under my definition of proof game. Thanks, @rooklift !

rooklift commented 3 years ago

It does I'm afraid, I did about 53 moves without captures / pawn pushes.

It would be legal in normal Chess since both players have to agree to draw.

tromp commented 3 years ago

Ah yes, your last pawn/capture move was 35. f4 But you could have transposed moves 35 - 38 to make it 38. f4 and then all is fine and dandy.

rooklift commented 3 years ago

I guess this eliminates all doubt. But can you clarify what you're willing to accept wrt 50/75 move rule?

1. b3 a5 2. b4 axb4 3. a4 b3 4. a5 b2 5. Nc3 b1=R 6. a6 Nc6 7. a7 Rb8 8. a8=Q
Rb6 9. Qa2 Ra6 10. Qb1 Raa8 11. d4 Na7 12. Na2 c5 13. c4 cxd4 14. c5 b5 15. c6
b4 16. c7 Ba6 17. c8=Q b3 18. Qc8c2 b2 19. e4 f5 20. exf5 e5 21. f6 Bd6 22. f7+
Ke7 23. f8=B+ Ke8 24. Be7 Bc7 25. Bh4 g5 26. Bg3 h6 27. h4 Nf6 28. hxg5 Nd5 29.
g6 Nb4 30. g7 Rf8 31. g8=N e4 32. Qa4 e3 33. Bd3 e2 34. Kd2 e1=R 35. Qb1c2 Rb5
36. Qab3 Ra5 37. Qd5 Ra4 38. Bh4 Qe7 39. f4 Kd8 40. Bf6 Kc8 41. Qcc6 Kb8 42. Bg5
Re3 43. Nf6 Rh3 44. Ne8 Rf5 45. Qe4 Rc5 46. Bh4 Ba5 47. Ke2 Nb5 48. Qc2 Ra7 49.
Bg3 Nc7 50. Kf3 Qg5 51. Qed5 Bc4 52. Ke4 Qh4 53. Ke5 Qg4 54. Kd6 Nb5+ 55. Ke7
Na3 56. Kd6 Rc7 57. Qe2 Bb5 58. Bb1 Bd3 59. Qe7 Be2 60. Qf8 Nd3 61. Be3 Nc1 62.
Nc3 Na2 63. Bc2 Bb4 64. Ne4 Be1 65. Rc1 Rb7 66. Bb1 Rc7 67. Bh2 Rb7 68. Nf3 Bf2
69. Ne1 Bg1 70. Nd3 Rc7 71. Bf2 Rb7 72. Bh4 Rc7 73. Bf6 Rb7 74. Qg5 Rc7 75. Qg6
Rb7 76. Ng3 Rc7 77. Nf5 Rb7 78. Qf3 Bf2 79. Qe3 Be1 80. Rf1 Qh4 81. Rf3 Qg4 82.
Rg3 Qh4 83. Rg5 Qg4 84. Qgf7 Rbc7 85. Rg7 Rb7 86. Rh7 Rbc7 87. Qg6 Ka8 88. Qe4+
1/2-1/2
tromp commented 3 years ago

I happily ignore the 50 move rule in my definition of valid game. I have actually seen a position that can only be reached after 50+ non-pawn/capture moves, but the odds of such positions appearing in my sample are so astronomically small as to have no effect on my estimates.