What's up with this endgame?

[Paloma]

Thanks

[zullil]

[d]8/3b2k1/1p3pp1/3p1p2/3P1P2/P3P3/5KP1/5B2 b - -

At depth 100/187 SF dev finally shows +2.96 with analysis contempt on (c=24 so real eval is probably around +3.2 is my guess). So this might just be mate in N from this position.

I doubt that this position is a win for White. Black should simply avoid gxf4 and not allow the white king to penetrate across the c-file.

But, who knows.

[Ajedrecista]

Hello:

[d]8/3b2k1/1p3pp1/3p1p2/3P1P2/P3P3/5KP1/5B2 b - -

At depth 100/187 SF dev finally shows +2.96 with analysis contempt on (c=24 so real eval is probably around +3.2 is my guess). So this might just be mate in N from this position.

I doubt that this position is a win for White. Black should simply avoid gxf4 and not allow the white king to penetrate across the c-file.

But, who knows.

Could this position be solved by Freezer and/or FinalGen? I think it is a suitable position: 1 minor piece vs 1 minor piece and some blocked pawns... however, the elapsed time to get the solution must be huge, as well as RAM and storage space available, because there are 7 + 7 = 14 pieces OTB.

To get an idea of the size of the problem, there are 5,748,050 unique positions after only 8 plies, counted with JetChess [not to be confused with perft(8) of this position, which is 1,406,028,571].

Regards from Spain.

Ajedrecista.

[zullil]

[d]8/3b2k1/1p3pp1/3p1p2/3P1P2/P3P3/5KP1/5B2 b - -

At depth 100/187 SF dev finally shows +2.96 with analysis contempt on (c=24 so real eval is probably around +3.2 is my guess). So this might just be mate in N from this position.

I doubt that this position is a win for White. Black should simply avoid gxf4 and not allow the white king to penetrate across the c-file.

But, who knows.

Well, some forward and backward analysis suggests that I was wrong. Cfish-dev says:

+3.84 40... Kf7 41. Ke1 Ke7 42. Kd2 Be8 43. Kc3 Kd6 44. Bd3 Ba4 45. Kb4 Bd1 46. a4 Kc6 47. Bb5+ Kb7 48. Bf1 Bh5 49. g3 g5 50. Bd3 Bg6 51. a5 Ka7 52. Bb5 Bh5 53. Bd7 Kb7 54. Bxf5 Bf3 55. Bc2 Bg2 56. Bd3 bxa5+ 57. Kxa5 Kc6 58. Bc2 Bf1 59. Ba4+ Kc7 60. Bb5 Bh3 61. Be2 Kc6 62. Ba6 Bg4 63. Bd3 Bh5 64. Bb5+ Kc7 65. Ba6 Bd1 66. Bd3 Kc6 67. Bb5+ Kb7 68. Bf1 Kc6 69. Bh3 Be2 70. Bf5 Bc4 71. Be6 Be2 72. Bf7 Bd3 73. Be8+ Kc7 74. Bh5 Kb7 75. Bd1 Kc6 76. Bg4 Be4 77. Be6 Bc2 78. Ka6 Bg6 79. Ka7 Kd6 80. Bg4 Kc7 81. Bf3 Kc6 82. Kb8 Bf5 83. Bh5 Kb6 84. Be8 Bh3 85. Bf7 gxf4 86. gxf4 Kc6 87. Be8+ Kb6 88. Bg6 Bd7 89. Bc2 Be6 90. Bb3 Kc6 91. Ba4+ Kd6 (depth 87, 0:30:47)

[Uri Blass]

I wonder if the following position that happened in the game is also a win for white or maybe in the game white did a mistake and in the following position cannot win in case black play the right move.

[d]8/K1k5/1p3p2/3p1pp1/3P1P2/PB1bP1P1/8/8 b - - 4 53

[Vinvin]

[d]8/3b2k1/1p3pp1/3p1p2/3P1P2/P3P3/5KP1/5B2 b - -

At depth 100/187 SF dev finally shows +2.96 with analysis contempt on (c=24 so real eval is probably around +3.2 is my guess). So this might just be mate in N from this position.

I doubt that this position is a win for White. Black should simply avoid gxf4 and not allow the white king to penetrate across the c-file.

But, who knows.

Well, some forward and backward analysis suggests that I was wrong. Cfish-dev says:

+3.84 40... Kf7 41. Ke1 Ke7 42. Kd2 Be8 43. Kc3 Kd6 44. Bd3 Ba4 45. Kb4 Bd1 46. a4 Kc6 47. Bb5+ Kb7 48. Bf1 Bh5 49. g3 g5 50. Bd3 Bg6 51. a5 Ka7 52. Bb5 Bh5 53. Bd7 Kb7 54. Bxf5 Bf3 55. Bc2 Bg2 56. Bd3 bxa5+ 57. Kxa5 Kc6 58. Bc2 Bf1 59. Ba4+ Kc7 60. Bb5 Bh3 61. Be2 Kc6 62. Ba6 Bg4 63. Bd3 Bh5 64. Bb5+ Kc7 65. Ba6 Bd1 66. Bd3 Kc6 67. Bb5+ Kb7 68. Bf1 Kc6 69. Bh3 Be2 70. Bf5 Bc4 71. Be6 Be2 72. Bf7 Bd3 73. Be8+ Kc7 74. Bh5 Kb7 75. Bd1 Kc6 76. Bg4 Be4 77. Be6 Bc2 78. Ka6 Bg6 79. Ka7 Kd6 80. Bg4 Kc7 81. Bf3 Kc6 82. Kb8 Bf5 83. Bh5 Kb6 84. Be8 Bh3 85. Bf7 gxf4 86. gxf4 Kc6 87. Be8+ Kb6 88. Bg6 Bd7 89. Bc2 Be6 90. Bb3 Kc6 91. Ba4+ Kd6 (depth 87, 0:30:47)

Please, could you check the eval by playing the main line move by move ?
I have some doubts with long lines in Stockfish. They are sometimes wrong.
In the line displayed here 77...Bc2 is losing but 77...Bd3 seems drawish.

[Ovyron]

Wow! Very impressive developments on the analysis. If that was lost then I wonder what was black's losing move, but it seems Stockfish was giving drawish score for mate in N position.

I wonder if the following position that happened in the game is also a win for white or maybe in the game white did a mistake and in the following position cannot win in case black play the right move.

This is doubtful. My opponent was using some weeks for the moves, in that time he played what he believed was winning, and he was right, so if the position in the OP is a mate in something, my opponent picked it because he figured that out already, so I don't think he messed up later on.

I still have private Stockfish 9 with learning around, now that I know the depths required to see the light it's possible I can solve it and answer these questions.

[Eelco de Groot]

[d]8/3b2k1/1p3pp1/3p1p2/3P1P2/P3P3/5KP1/5B2 b - -

At depth 100/187 SF dev finally shows +2.96 with analysis contempt on (c=24 so real eval is probably around +3.2 is my guess). So this might just be mate in N from this position.

I doubt that this position is a win for White. Black should simply avoid gxf4 and not allow the white king to penetrate across the c-file.

But, who knows.

Well, some forward and backward analysis suggests that I was wrong. Cfish-dev says:

+3.84 40... Kf7 41. Ke1 Ke7 42. Kd2 Be8 43. Kc3 Kd6 44. Bd3 Ba4 45. Kb4 Bd1 46. a4 Kc6 47. Bb5+ Kb7 48. Bf1 Bh5 49. g3 g5 50. Bd3 Bg6 51. a5 Ka7 52. Bb5 Bh5 53. Bd7 Kb7 54. Bxf5 Bf3 55. Bc2 Bg2 56. Bd3 bxa5+ 57. Kxa5 Kc6 58. Bc2 Bf1 59. Ba4+ Kc7 60. Bb5 Bh3 61. Be2 Kc6 62. Ba6 Bg4 63. Bd3 Bh5 64. Bb5+ Kc7 65. Ba6 Bd1 66. Bd3 Kc6 67. Bb5+ Kb7 68. Bf1 Kc6 69. Bh3 Be2 70. Bf5 Bc4 71. Be6 Be2 72. Bf7 Bd3 73. Be8+ Kc7 74. Bh5 Kb7 75. Bd1 Kc6 76. Bg4 Be4 77. Be6 Bc2 78. Ka6 Bg6 79. Ka7 Kd6 80. Bg4 Kc7 81. Bf3 Kc6 82. Kb8 Bf5 83. Bh5 Kb6 84. Be8 Bh3 85. Bf7 gxf4 86. gxf4 Kc6 87. Be8+ Kb6 88. Bg6 Bd7 89. Bc2 Be6 90. Bb3 Kc6 91. Ba4+ Kd6 (depth 87, 0:30:47)

Please, could you check the eval by playing the main line move by move ?
I have some doubts with long lines in Stockfish. They are sometimes wrong.
In the line displayed here 77...Bc2 is losing but 77...Bd3 seems drawish.

I can confirm that backwards solving the line from CFish seems to get stuck on move 77 and Bd3 so far is the only move that does not lose. But no tablebases etc. used. 1.23 I consider a draw. 77...Bc2 would lose.

[d]8/8/2k1Bp2/K2p2p1/3PbP2/4P1P1/8/8 b - -

Engine: Kaissa IV NoContempt (512 MB)
by T. Romstad, M. Costalba, J. Kiiski, G. Linscott

59 10:53 +1.23 77...Bd3 78.Kb4 Be4 79.Bg4 Bd3
80.Bh3 Be2 81.Be6 Bf3 82.Bf5 Be2
83.Kc3 Kd6 84.Bd3 Bf3 85.Kd2 Bg4
86.Bb1 Bd7 87.Bc2 Bg4 88.Bd3 Bc8
89.Kc3 Bg4 90.Bb5 Bf5 (1.839.438.988) 2814

59 10:53 +6.01 77...Bg6 78.Ka6 Be4 79.Bf7 Bd3+
80.Ka7 Bf5 81.Kb8 Kd6 82.Kb7 Bg4
83.Kb6 Bf5 84.Bh5 Bc8 85.Bd1 Bf5
86.Kb7 Bh3 87.Be2 Kd7 88.Bb5+ Kd6
89.Ba6 Bd7 90.Bd3 Bg4 (1.839.438.988) 2814

59 10:53 +6.01 77...Bc2 78.Ka6 Bg6 79.Ka7 Kd6
80.Bg4 Kc7 81.Bf3 Kc6 82.Kb8 Bf5
83.Bh5 Kb6 84.Be8 gxf4 85.gxf4 Bg4
86.Bg6 Bd7 87.Bd3 Kc6 88.Ba6 Bh3
89.Bb7+ Kd6 90.Bc8 Bf1 (1.839.438.988) 2814

(At this point it is 20 moves without a non reversible move says Shredder GUI but I don't think that is very important yet.) I could post the .pgn of the line but an old Shredder GUI bug then stops analysis

Here is the pgn:



[pgn][Event "?"] [Site "?"] [Date "2019.07.21"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. d4 d5 2. Bf4 c5 3. c3 Nf6 4. e3 e6 5. Nd2 Nc6 6. Ngf3 Nh5 7. Bg5 f6 8. Bh4 g6 9. Be2 Ng7 10. Bg3 cxd4 11. cxd4 Nf5 12. O-O Kf7 13. a3 h5 14. Nh4 Nxg3 15. hxg3 Kg7 16. f4 Bd7 17. Nb3 b6 18. Bd3 Ne7 19. Rc1 Be8 20. g4 Rc8 21. Qf3 hxg4 22. Qxg4 Rh6 23. Nd2 Bd7 24. Qg3 Qe8 25. Ndf3 Nf5 26. Nxf5+ exf5 27. Rxc8 Qxc8 28. Qe1 Bd6 29. Kf2 b5 30. Qa5 Qb7 31. Rc1 Rh8 32. Bf1 Qb6 33. Qxb6 axb6 34. Ne1 b4 35. axb4 Ra8 36. Rc3 Ra1 37. Ra3 Rxe1 38. Kxe1 Bxb4+ 39. Kf2 Bxa3 40. bxa3 Ba4 (40... Kf7 41. Ke1 Ke7 42. Kd2 Be8 43. Kc3 Kd6 44. Bd3 Ba4 45. Kb4 Bd1 46. a4 Kc6 47. Bb5+ Kb7 48. Bf1 Bh5 49. g3 g5 50. Bd3 Bg6 51. a5 Ka7 52. Bb5 Bh5 53. Bd7 Kb7 54. Bxf5 Bf3 55. Bc2 Bg2 56. Bd3 bxa5+ 57. Kxa5 Kc6 58. Bc2 Bf1 59. Ba4+ Kc7 60. Bb5 Bh3 61. Be2 Kc6 62. Ba6 Bg4 63. Bd3 Bh5 64. Bb5+ Kc7 65. Ba6 Bd1 66. Bd3 Kc6 67. Bb5+ Kb7 68. Bf1 Kc6 69. Bh3 Be2 70. Bf5 Bc4 71. Be6 Be2 72. Bf7 Bd3 73. Be8+ Kc7 74. Bh5 Kb7 75. Bd1 Kc6 76. Bg4 Be4 77. Be6 Bc2 $2 78. Ka6 Bg6 79. Ka7 Kd6 80. Bg4 Kc7 81. Bf3 Kc6 82. Kb8 Bf5 83. Bh5 Kb6 84. Be8 Bh3 85. Bf7 gxf4 86. exf4 Kc6 87. Be8+ Kb6 88. Bg6 Bd7 89. Bc2 Be6 90. Bb3 Kc6 91. Ba4+ Kd6) 41. Ke1 Kf7 42. Kd2 Ke7 43. Kc3 Kd6 44. Bd3 Kc7 45. Kb4 Bd1 46. Kb5 Bg4 47. Ka6 Bd1 48. Bb5 Bc2 49. Be8 Bd3+ 50. Ka7 g5 51. g3 Be2 52. Ba4 Bd3 53. Bb3 gxf4 54. exf4 Be4 55. Ba4 Bf3 56. Ka6 Be2+ 57. Bb5 Bg4 58. Bd3 Bh3 59. Kb5 Kb7 60. a4 Kc7 61. a5 bxa5 62. Kxa5 Kc6 63. Bb5+ Kc7 64. Ka6 Bg2 65. Be8 Bf1+ 66. Ka5 Bd3 67. Bg6 Bc2 68. Kb5 Kd6 69. Bh5 Bd3+ 70. Kb6 Bb1 71. Kb7 Be4 72. Kc8 Ke7 73. Kc7 Bd3 74. Kc6 Ke6 75. Be8 Bb1 76. Kc5 Be4 77. Bb5 Bh1 78. Ba6 Be4 79. Bb7 Kd7 80. Bxd5 Bc2 81. Bf7 Bd1 82. Bc4 Bf3 83. Bd3 Be4 84. Kc4 {Black Resigns. 1-0} *[/pgn]

[zullil]

[d]8/3b2k1/1p3pp1/3p1p2/3P1P2/P3P3/5KP1/5B2 b - - 0 40

+7.52 40... g5 41. Ke1 Kf8 42. Kd2 Ke7 43. Kc3 Be8 44. Kb4 Kd8 45. Bb5 Bh5 46. Bc6 Bf7 47. Kb5 Kc7 48. g3 Bg8 49. Be8 Kd8 50. Bg6 Kc7 51. Bh5 Be6 52. Kb4 Bc8 53. Be2 Bd7 54. a4 Be8 55. Bb5 Bg6 56. a5 bxa5+ 57. Kxa5 Bh5 58. Bd3 Kc6 59. Bc2 Be2 60. Bxf5 Bf3 61. Be6 Be2 62. Bg8 Bd3 63. Bf7 Be4 64. Be8+ Kc7 65. Kb5 Kd6 66. Bf7 Bd3+ 67. Kb6 gxf4 68. gxf4 Bf1 69. Bg6 Bh3 70. Kb7 Bg4 71. Bd3 Be6 72. Bb5 Bh3 73. Kb6 Bf5 74. Bc6 Be4 75. Be8 Ke7 76. Bb5 Kd6 77. Bc6 Bh1 78. Be8 Be4 79. Kb7 Bd3 80. Bf7 f5 81. Be8 Bf1 82. Kb6 Be2 83. Bc6 Bd1 84. Bb5 Bc2 85. Kb7 Bd1 86. Kc8 (depth 78, 8:57:10)

Looks like White wins.

[Eelco de Groot]

Now Kaissa seems to get stuck a little here Louis... Assuming I entered the line correctly into Uly's pgn so far. Could it be a tablebase thing? But 63...Be4 seems just a wrong move...

Or is it just because you disabled nullmove in CFish? That I can believe, if it is some sort of Zugzwang and Stockfish also would not see it on time..


[d]8/5B2/2k2p2/K2p2p1/3P1P2/3bP1P1/8/8 b - -

Engine: Kaissa IV NoContempt (512 MB)
by T. Romstad, M. Costalba, J. Kiiski, G. Linscott

56 3:14 +1.23 63...Bf1 64.Kb4 Be2 65.Bg6 Bf3
66.Be8+ Kb6 67.Ba4 Be4 68.Kc3 Kc7
69.Bd1 Kd6 70.Be2 Kc6 71.Bd3 Bf3
72.Bc2 Kd6 73.Kd2 Bg4 74.Bd3 Bd7
75.Kc3 Bg4 76.Bb1 Kc6 (531.595.387) 2733

56 3:14 +1.23 63...Be2 64.Be8+ Kc7 65.Kb4 Kd6
66.Bg6 Kc6 67.Bb1 Kd6 68.Bf5 Kc6
69.Kc3 Bf3 70.Kd3 Kd6 71.Bg6 Bg2
72.Kd2 Bf3 73.Bf7 Be4 74.Kc3 Kc6
75.Be8+ Kd6 76.Bb5 Bf3 (531.595.387) 2733

55 3:14 +6.49 63...Bb1 64.Ka6 Bh7 65.Ka7 Bd3
66.Kb8 Bf5 67.Bh5 Kb6 68.Be8 Be6
69.Bg6 Kc6 70.Bd3 Bd7 71.Ba6 gxf4
72.gxf4 Bf5 73.Bb7+ Kd6 74.Bc8 Bd3
75.Kb7 Be2 76.Kb6 Bd1 (531.595.387) 2733

[pgn] [Event "?"] [Site "?"] [Date "2019.07.21"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. d4 d5 2. Bf4 c5 3. c3 Nf6 4. e3 e6 5. Nd2 Nc6 6. Ngf3 Nh5 7. Bg5 f6 8. Bh4 g6 9. Be2 Ng7 10. Bg3 cxd4 11. cxd4 Nf5 12. O-O Kf7 13. a3 h5 14. Nh4 Nxg3 15. hxg3 Kg7 16. f4 Bd7 17. Nb3 b6 18. Bd3 Ne7 19. Rc1 Be8 20. g4 Rc8 21. Qf3 hxg4 22. Qxg4 Rh6 23. Nd2 Bd7 24. Qg3 Qe8 25. Ndf3 Nf5 26. Nxf5+ exf5 27. Rxc8 Qxc8 28. Qe1 Bd6 29. Kf2 b5 30. Qa5 Qb7 31. Rc1 Rh8 32. Bf1 Qb6 33. Qxb6 axb6 34. Ne1 b4 35. axb4 Ra8 36. Rc3 Ra1 37. Ra3 Rxe1 38. Kxe1 Bxb4+ 39. Kf2 Bxa3 40. bxa3 Ba4 (40... Kf7 41. Ke1 Ke7 42. Kd2 Be8 43. Kc3 Kd6 44. Bd3 Ba4 45. Kb4 Bd1 46. a4 Kc6 47. Bb5+ Kb7 48. Bf1 Bh5 49. g3 g5 50. Bd3 Bg6 51. a5 Ka7 52. Bb5 Bh5 53. Bd7 Kb7 54. Bxf5 Bf3 55. Bc2 Bg2 56. Bd3 bxa5+ 57. Kxa5 Kc6 58. Bc2 Bf1 59. Ba4+ Kc7 60. Bb5 Bh3 61. Be2 Kc6 62. Ba6 Bg4 63. Bd3 Bh5 64. Bb5+ Kc7 65. Ba6 Bd1 66. Bd3 Kc6 67. Bb5+ Kb7 68. Bf1 Kc6 69. Bh3 Be2 70. Bf5 Bc4 71. Be6 Be2 72. Bf7 Bd3 73. Be8+ Kc7 74. Bh5 Kb7 75. Bd1 Kc6 76. Bg4 Be4 77. Be6 Bc2 $2 78. Ka6 Bg6 79. Ka7 Kd6 80. Bg4 Kc7 81. Bf3 Kc6 82. Kb8 Bf5 83. Bh5 Kb6 84. Be8 Bh3 85. Bf7 gxf4 86. exf4 Kc6 87. Be8+ Kb6 88. Bg6 Bd7 89. Bc2 Be6 90. Bb3 Kc6 91. Ba4+ Kd6) (40... g5 41. Ke1 Kf8 42. Kd2 Ke7 43. Kc3 Be8 44. Kb4 Kd8 45. Bb5 Bh5 46. Bc6 Bf7 47. Kb5 Kc7 48. g3 Bg8 49. Be8 Kd8 50. Bg6 Kc7 51. Bh5 Be6 52. Kb4 Bc8 53. Be2 Bd7 54. a4 Be8 55. Bb5 Bg6 56. a5 bxa5+ 57. Kxa5 Bh5 58. Bd3 Kc6 59. Bc2 Be2 60. Bxf5 Bf3 61. Be6 Be2 62. Bg8 Bd3 63. Bf7 {diagram above} Be4 64. Be8+ Kc7 65. Kb5 Kd6 66. Bf7 Bd3+ 67. Kb6 gxf4 68. gxf4 Bf1 69. Bg6 Bh3 70. Kb7 Bg4 71. Bd3 Be6 72. Bb5 Bh3 73. Kb6 Bf5 74. Bc6 Be4 75. Be8 Ke7 76. Bb5 Kd6 77. Bc6 Bh1 78. Be8 Be4 79. Kb7 Bd3 80. Bf7 f5 81. Be8 Bf1 82. Kb6 Be2 83. Bc6 Bd1 84. Bb5 Bc2 85. Kb7 Bd1 86. Kc8) 41. Ke1 Kf7 42. Kd2 Ke7 43. Kc3 Kd6 44. Bd3 Kc7 45. Kb4 Bd1 46. Kb5 Bg4 47. Ka6 Bd1 48. Bb5 Bc2 49. Be8 Bd3+ 50. Ka7 g5 51. g3 Be2 52. Ba4 Bd3 53. Bb3 gxf4 54. exf4 Be4 55. Ba4 Bf3 56. Ka6 Be2+ 57. Bb5 Bg4 58. Bd3 Bh3 59. Kb5 Kb7 60. a4 Kc7 61. a5 bxa5 62. Kxa5 Kc6 63. Bb5+ Kc7 64. Ka6 Bg2 65. Be8 Bf1+ 66. Ka5 Bd3 67. Bg6 Bc2 68. Kb5 Kd6 69. Bh5 Bd3+ 70. Kb6 Bb1 71. Kb7 Be4 72. Kc8 Ke7 73. Kc7 Bd3 74. Kc6 Ke6 75. Be8 Bb1 76. Kc5 Be4 77. Bb5 Bh1 78. Ba6 Be4 79. Bb7 Kd7 80. Bxd5 Bc2 81. Bf7 Bd1 82. Bc4 Bf3 83. Bd3 Be4 84. Kc4 {Black Resigns. 1-0} * [/pgn]