Queen and pawn endgame

[Maxwell86]

Mmmmm, it's not easy to determine whether the queen endgame is winning for white or not. There are many branches.

According to your shootout (thanks a lot for the effort!), white scores 80%, but still it's hard to draw any conclusions, I think. Moreover, the time control is quite short. (These engines can barely figure out a simple pawn endgame in 1 minute )

[Rodolfo Leoni]

Mmmmm, it's not easy to determine whether the queen endgame is winning for white or not. There are many branches.

According to your shootout (thanks a lot for the effort!), white scores 80%, but still it's hard to draw any conclusions, I think. Moreover, the time control is quite short. (These engines can barely figure out a simple pawn endgame in 1 minute )

I just started a test-match with an old Persistent Hash Stockfish version vs. AsmFishW, fixed depth 30, 100 games. This will also be useful to test PH feature a bit better and, hopefully, will confirm Qg2 draw.

I hope to have some interesting results within 2-3 days...

[zullil]

and if you repeat that one from the position Bart posted, to help your search horizon?

SF should not be changing all pawns on the queen side here, rather go for an f3-f4-f5 storm, something like that.

my 3 minute-long quick experiments with Komodo and SF lead to increasing score with both engines in most of the lines.

but again, my engines are, of course, buggy.

[d] 8/1p3Qpk/p2q3p/7P/6P1/3K1P2/P1P5/8 w - - 5 45

asmFish sees no progress for White. The evaluation has remained constant for many iterations. I suspect that GM Michiels's original belief---that the position is a draw---is correct. I also agree with him that the time control you used for your shootout is likely too short for correct play.

Code: Select all

+0.93 45. Kc4 Qc6+ 46. Kd3 Qd6+ 47. Kc3 Qe5+ 48. Kc4 b5+ 49. Kd3 Qd6+ 50. Ke4 Qb4+ 51. Ke5 Kh8 52. Qd5 Qb2+ 53. Kd6 a5 54. Qa8+ Kh7 55. Qxa5 Qd4+ 56. Kc6 Qc4+ 57. Kb7 Qxc2 58. Qa3 Qc4 59. Qb3 Kh8 60. Kb6 Qd4+ 61. Kc6 Qf6+ 62. Kxb5 Qe5+ 63. Kc6 Qe8+ 64. Kd5 Qd7+ 65. Ke5 Qc7+ 66. Kd4 Qa7+ 67. Kd3 Qf2 68. Qb8+ Kh7 69. Qf4 Qxa2 70. Qc4 Qa3+ 71. Ke2 Qb2+ 72. Kf1 Qb1+ 73. Kg2 Qb2+ 74. Kh3 Qf2 75. Qd3+ Kg8 76. Qd5+ Kf8 77. Qd8+ Kf7 78. Qc7+ Kg8 79. Qg3 Qe2 80. Qg2 Qc4 81. Qf2 Qd3 82. Qa2+ Kh7 83. Kg2 Qd1 84. Qc4 (depth 66, 1:10:38)

[Lyudmil Tsvetkov]

and if you repeat that one from the position Bart posted, to help your search horizon?

SF should not be changing all pawns on the queen side here, rather go for an f3-f4-f5 storm, something like that.

my 3 minute-long quick experiments with Komodo and SF lead to increasing score with both engines in most of the lines.

but again, my engines are, of course, buggy.

[d] 8/1p3Qpk/p2q3p/7P/6P1/3K1P2/P1P5/8 w - - 5 45

asmFish sees no progress for White. The evaluation has remained constant for many iterations. I suspect that GM Michiels's original belief---that the position is a draw---is correct. I also agree with him that the time control you used for your shootout is likely too short for correct play.

Code: Select all

+0.93 45. Kc4 Qc6+ 46. Kd3 Qd6+ 47. Kc3 Qe5+ 48. Kc4 b5+ 49. Kd3 Qd6+ 50. Ke4 Qb4+ 51. Ke5 Kh8 52. Qd5 Qb2+ 53. Kd6 a5 54. Qa8+ Kh7 55. Qxa5 Qd4+ 56. Kc6 Qc4+ 57. Kb7 Qxc2 58. Qa3 Qc4 59. Qb3 Kh8 60. Kb6 Qd4+ 61. Kc6 Qf6+ 62. Kxb5 Qe5+ 63. Kc6 Qe8+ 64. Kd5 Qd7+ 65. Ke5 Qc7+ 66. Kd4 Qa7+ 67. Kd3 Qf2 68. Qb8+ Kh7 69. Qf4 Qxa2 70. Qc4 Qa3+ 71. Ke2 Qb2+ 72. Kf1 Qb1+ 73. Kg2 Qb2+ 74. Kh3 Qf2 75. Qd3+ Kg8 76. Qd5+ Kf8 77. Qd8+ Kf7 78. Qc7+ Kg8 79. Qg3 Qe2 80. Qg2 Qc4 81. Qf2 Qd3 82. Qa2+ Kh7 83. Kg2 Qd1 84. Qc4 (depth 66, 1:10:38)

that is what engines use for their testing.

sometimes, larger number of STC games are more meaningful than a single LTC search.

large number of statistically relevant games is actually what all engines use as a reference.

mostly, those stats would be true, though there are some exceptions.

it is a pity that I don't quite have the energy and resilience to go through your SF line now, too much analysis is sometimes counter-productive, but I might look at some nodes at a later point.

btw., someone analysing at LTC with other engine than SF?

[Lyudmil Tsvetkov]

Mmmmm, it's not easy to determine whether the queen endgame is winning for white or not. There are many branches.

According to your shootout (thanks a lot for the effort!), white scores 80%, but still it's hard to draw any conclusions, I think. Moreover, the time control is quite short. (These engines can barely figure out a simple pawn endgame in 1 minute )

thanks a lot for your way of replying, Bart!

that is one attitude I really cherish very much.

it is easy to proceed with discussion like that.

of course, TC is too short, and I am too short of resources too...

not easy to conclude anything, even from the scarce stats.

possibly only thing that could be said is that white has winning chances.

I am afraid of a full analysis now, as I am too exhausted from the previous positions I analysed, I retain the right to think this is a white win, and anyone esle could stick to their guns too.

[zullil]

quick shootout with SF and Komodo, 10 games each, 1 min. per game, from the position Bart posted:

[d]8/1p3Qpk/p2q3p/7P/6P1/3K1P2/P1P5/8 w - - 0 1

12 white wins, 8 draws

SF wins half, Komodo 7

conclude from that what you want.

2 white wins:

[pgn][Event "Shootout (Stockfish864POPCNT, Blitz 1m)"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "New game"]
[Black "?"]
[Result "1-0"]
[SetUp "1"]
[FEN "8/1p3Qpk/p2q3p/7P/6P1/3K1P2/P1P5/8 w - - 0 1"]
[PlyCount "111"]

1. Kc3 {0.53/18 1} Qe5+ {0.81/20 2} 2. Kc4 {1.14/21 2} Qb5+ {1.07/22 3} 3. Kd4
{1.10/21 1} Qb6+ {1.10/23 2} 4. Ke5 {1.14/23 8 (Kc3)} Qb2+ {1.06/22 3 (Qe3+)}
5. Kd6 {1.20/22 1} Qb6+ {1.26/22 3} 6. Kd7 {1.28/23 1} Qc6+ {1.23/22 2} 7. Kd8
{1.21/23 1} b5 {1.31/23 2} 8. Qf5+ {1.33/22 1} Kh8 {1.28/23 2} 9. Qe4 {1.27/21
0} Qf6+ {1.10/22 3} 10. Kc7 {1.08/23 0} Qf7+ {1.15/24 2} 11. Kb6 {1.15/24 1}
Qxa2 {1.17/24 2} 12. f4 {1.19/24 1} Qg8 {1.19/25 2} 13. f5 {1.19/25 1} b4 {1.
04/24 3} 14. Qe6 {1.12/21 1} Qa8 {1.25/23 3} 15. f6 {1.26/22 0} Qd8+ {1.25/22 1
} 16. Kxa6 {1.24/24 1} gxf6 {1.25/24 1} 17. Qf5 {1.25/24 0} Qd4 {1.26/23 1} 18.
Kb5 {1.26/25 2} Qd6 {1.25/23 1 (Qb2)} 19. Qe4 {1.26/21 1 (Ka4)} Qb8+ {1.26/22 1
} 20. Kc4 {1.24/22 1} b3 {1.17/22 1} 21. cxb3 {1.22/23 1} Qc7+ {1.16/23 1} 22.
Kd3 {1.57/24 7} Qg3+ {1.59/20 1} 23. Qe3 {1.71/20 1} Qd6+ {1.77/21 2} 24. Qd4 {
1.67/22 1} Qg3+ {1.82/19 1} 25. Kc4 {1.82/21 1} Qc7+ {1.86/19 1} 26. Qc5 {1.85/
22 1} Qf4+ {1.86/21 1} 27. Kb5 {1.93/23 1} Qxg4 {2.01/21 2} 28. Qf8+ {2.16/21 0
} Kh7 {2.16/22 1} 29. Qf7+ {2.47/21 1} Kh8 {2.47/22 0} 30. Qxf6+ {2.45/23 1}
Kh7 {2.54/22 0} 31. Qe7+ {2.58/23 1} Kh8 {2.61/19 0 (Kg8)} 32. Qe5+ {2.41/20 1}
Kg8 {2.44/18 0} 33. Qd5+ {2.61/19 1} Kh8 {2.69/21 1} 34. b4 {2.69/20 0} Qg7 {
2.68/20 1} 35. Qc6 {2.73/17 0} Qg5+ {2.67/19 1 (Qe5+)} 36. Ka6 {2.78/19 0} Qxh5
{2.72/20 0} 37. b5 {2.83/19 0} Qe2 {2.83/19 0} 38. Qxh6+ {3.46/19 2} Kg8 {3.46/
1 0} 39. Qd6 {3.52/22 0} Kf7 {3.52/19 0} 40. Kb6 {3.59/23 0} Ke8 {3.66/23 1}
41. Qd5 {3.66/25 0} Ke7 {3.66/23 0 (Qb2)} 42. Kc6 {3.66/22 0} Qg4 {3.40/19 0}
43. Qd6+ {3.29/20 1} Ke8 {3.41/21 0} 44. b6 {3.58/21 0} Qc4+ {3.66/19 0 (Qf3+)}
45. Qc5 {3.41/21 0} Qe4+ {3.58/21 0 (Qe6+)} 46. Kc7 {3.66/23 0 (Qd5)} Qf4+ {3.
35/21 0 (Qh7+)} 47. Kc8 {2.72/21 1 (Qd6)} Qg4+ {3.35/21 0} 48. Kb7 {3.66/21 0}
Qh4 {3.74/20 0} 49. Qd6 {3.61/23 0} Qf2 {3.58/21 0} 50. Kb8 {3.74/21 0} Qb2 {
3.74/22 0 (Qa2)} 51. b7 {3.74/25 0} Qa1 {3.91/22 0 (Qa2)} 52. Qe6+ {7.25/21 1
(Qc5)} Kd8 {3.27/17 0} 53. Qd5+ {2.80/19 0} Ke7 {2.72/13 0} 54. Kc7 {2.50/18 0}
Qc3+ {2.56/12 0 (Qc1+)} 55. Kb6 {7.26/19 1} Qb2+ {7.72/13 0 (Qb4+)} 56. Kc6 {
10.75/15 0} 1-0

[Event "Shootout (Komodo1164-bit, Blitz 1m) "]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "New game"]
[Black "?"]
[Result "1-0"]
[SetUp "1"]
[FEN "8/1p3Qpk/p2q3p/7P/6P1/3K1P2/P1P5/8 w - - 0 1"]
[PlyCount "117"]

1. Kc3 {0.45/18 1} Qe5+ {0.31/21 2} 2. Kd3 {0.43/22 3 (Kb3)} Qd6+ {0.52/20 1}
3. Kc4 {0.54/21 3} Qc6+ {0.63/20 1} 4. Kb3 {0.56/22 1} Qb5+ {0.68/22 4} 5. Ka3
{0.56/19 0} Qc5+ {0.70/20 1} 6. Kb2 {0.71/21 1} Qd4+ {0.72/20 1} 7. Kb3 {0.56/
21 0} Qe3+ {0.57/21 1} 8. Kc4 {0.69/21 1} Qe2+ {0.71/20 1} 9. Kd5 {0.73/20 1}
Qb5+ {0.73/21 2} 10. Kd4 {0.80/21 2} Qb6+ {0.71/21 1} 11. Ke5 {0.77/21 1} Qb2+
{0.74/21 1} 12. Kd6 {0.73/21 1} Qb6+ {0.71/22 1} 13. Kd7 {0.71/22 1} Qc6+ {0.
67/21 1} 14. Kd8 {0.74/21 1} b5 {0.75/21 1} 15. Qf5+ {0.79/22 2} Kh8 {0.80/20 1
} 16. Qc8 {0.92/21 2} Qb6+ {0.92/20 2 (Qd6+)} 17. Kd7+ {1.00/20 1} Kh7 {1.00/
20 0} 18. Qc6 {1.00/19 0} Qa7+ {0.97/21 1} 19. Kd6 {1.00/21 1} Qd4+ {1.00/21 2}
20. Qd5 {1.00/21 1} Qb6+ {1.02/21 1} 21. Kd7 {0.93/21 1} b4 {0.93/21 2} 22. Qe6
{1.02/20 1} Qb7+ {1.02/20 1} 23. Kd6 {1.02/21 1} Qb6+ {1.02/21 1} 24. Kd5 {1.
03/21 1} Qc7 {0.96/21 2 (Qa5+)} 25. Qxa6 {1.68/19 2} Kh8 {1.67/18 1 (Qxc2)} 26.
Qe6 {1.69/21 1} Qa5+ {1.67/22 3 (Qc3)} 27. Kd4 {1.74/23 2} Qa7+ {1.74/23 1} 28.
Kd3 {1.74/24 1} Qa3+ {1.74/23 1 (Qc5)} 29. Qb3 {1.74/19 0} Qa6+ {1.74/21 1} 30.
Qc4 {1.72/22 2} Qd6+ {1.76/23 1} 31. Qd4 {1.76/23 0} Qa6+ {1.76/24 1} 32. Kd2 {
1.77/22 1} Qa5 {1.78/22 1} 33. Kc1 {1.79/22 0 (Kd1)} Qxa2 {1.82/22 0} 34. Qxb4
{1.82/21 0} Qa8 {1.84/21 1 (Qa7)} 35. Qe4 {1.96/21 1} Qa3+ {2.04/21 1} 36. Kd1
{2.16/22 2} Qc3 {2.16/22 1 (Qd6+)} 37. Qd5 {2.18/23 1} Qa1+ {2.18/22 0} 38. Ke2
{2.18/22 0} Qb2 {2.18/23 1 (Qg1)} 39. Qd8+ {2.19/23 1} Kh7 {2.12/5 0} 40. Qd2 {
2.20/21 0 (Qd3+)} Qe5+ {2.22/22 1} 41. Kf1 {2.23/22 0} Qb2 {2.23/20 0} 42. Qd3+
{2.54/22 1} Kh8 {2.55/22 0} 43. Qd8+ {2.55/22 0} Kh7 {2.55/5 0} 44. c4 {2.55/
22 0} Qc1+ {2.55/23 0} 45. Ke2 {2.67/24 2} Qb2+ {2.67/21 0 (Qg1)} 46. Qd2 {2.
67/19 0} Qe5+ {2.68/18 0 (Qb6)} 47. Qe3 {2.68/20 0} Qb2+ {2.68/21 1} 48. Kf1 {
2.71/21 1} Qh2 {2.71/20 0} 49. c5 {2.83/20 1} Qh1+ {2.77/17 0} 50. Ke2 {2.89/
18 0} Qh2+ {2.89/16 0} 51. Kd3 {2.89/18 0} Qb8 {2.95/19 1} 52. c6 {2.96/19 0}
Kh8 {3.08/19 1} 53. Qe6 {3.24/17 0} Qb1+ {3.30/17 0} 54. Kd4 {3.71/16 0} Qb4+ {
3.82/17 1 (Qb8)} 55. Kd5 {4.03/19 0} Qb8 {4.75/17 1} 56. Qd7 {4.90/17 0} Qb3+ {
5.77/18 1} 57. Kc5 {5.92/19 0} Qe3+ {6.73/19 1} 58. Kb5 {7.22/17 0} Qb3+ {7.83/
19 1} 59. Ka6 {7.84/17 0} 1-0

[/pgn]

A quick check with asmFish suggests that 4... Qb2+ is losing in the first game above. The same error occurs in the same position in the second game, on move 11.

[Evert]

Mmmmm, it's not easy to determine whether the queen endgame is winning for white or not. There are many branches.

According to your shootout (thanks a lot for the effort!), white scores 80%, but still it's hard to draw any conclusions, I think. Moreover, the time control is quite short. (These engines can barely figure out a simple pawn endgame in 1 minute )

I just started a test-match with an old Persistent Hash Stockfish version vs. AsmFishW, fixed depth 30, 100 games. This will also be useful to test PH feature a bit better and, hopefully, will confirm Qg2 draw.

I hope to have some interesting results within 2-3 days...

If you want to know if the position is won or not, you can probably put it in FinalGen. I don't know how long that would take, but it's probably a better investment of CPU time.

[Lyudmil Tsvetkov]

quick shootout with SF and Komodo, 10 games each, 1 min. per game, from the position Bart posted:

[d]8/1p3Qpk/p2q3p/7P/6P1/3K1P2/P1P5/8 w - - 0 1

12 white wins, 8 draws

SF wins half, Komodo 7

conclude from that what you want.

2 white wins:

[pgn][Event "Shootout (Stockfish864POPCNT, Blitz 1m)"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "New game"]
[Black "?"]
[Result "1-0"]
[SetUp "1"]
[FEN "8/1p3Qpk/p2q3p/7P/6P1/3K1P2/P1P5/8 w - - 0 1"]
[PlyCount "111"]

1. Kc3 {0.53/18 1} Qe5+ {0.81/20 2} 2. Kc4 {1.14/21 2} Qb5+ {1.07/22 3} 3. Kd4
{1.10/21 1} Qb6+ {1.10/23 2} 4. Ke5 {1.14/23 8 (Kc3)} Qb2+ {1.06/22 3 (Qe3+)}
5. Kd6 {1.20/22 1} Qb6+ {1.26/22 3} 6. Kd7 {1.28/23 1} Qc6+ {1.23/22 2} 7. Kd8
{1.21/23 1} b5 {1.31/23 2} 8. Qf5+ {1.33/22 1} Kh8 {1.28/23 2} 9. Qe4 {1.27/21
0} Qf6+ {1.10/22 3} 10. Kc7 {1.08/23 0} Qf7+ {1.15/24 2} 11. Kb6 {1.15/24 1}
Qxa2 {1.17/24 2} 12. f4 {1.19/24 1} Qg8 {1.19/25 2} 13. f5 {1.19/25 1} b4 {1.
04/24 3} 14. Qe6 {1.12/21 1} Qa8 {1.25/23 3} 15. f6 {1.26/22 0} Qd8+ {1.25/22 1
} 16. Kxa6 {1.24/24 1} gxf6 {1.25/24 1} 17. Qf5 {1.25/24 0} Qd4 {1.26/23 1} 18.
Kb5 {1.26/25 2} Qd6 {1.25/23 1 (Qb2)} 19. Qe4 {1.26/21 1 (Ka4)} Qb8+ {1.26/22 1
} 20. Kc4 {1.24/22 1} b3 {1.17/22 1} 21. cxb3 {1.22/23 1} Qc7+ {1.16/23 1} 22.
Kd3 {1.57/24 7} Qg3+ {1.59/20 1} 23. Qe3 {1.71/20 1} Qd6+ {1.77/21 2} 24. Qd4 {
1.67/22 1} Qg3+ {1.82/19 1} 25. Kc4 {1.82/21 1} Qc7+ {1.86/19 1} 26. Qc5 {1.85/
22 1} Qf4+ {1.86/21 1} 27. Kb5 {1.93/23 1} Qxg4 {2.01/21 2} 28. Qf8+ {2.16/21 0
} Kh7 {2.16/22 1} 29. Qf7+ {2.47/21 1} Kh8 {2.47/22 0} 30. Qxf6+ {2.45/23 1}
Kh7 {2.54/22 0} 31. Qe7+ {2.58/23 1} Kh8 {2.61/19 0 (Kg8)} 32. Qe5+ {2.41/20 1}
Kg8 {2.44/18 0} 33. Qd5+ {2.61/19 1} Kh8 {2.69/21 1} 34. b4 {2.69/20 0} Qg7 {
2.68/20 1} 35. Qc6 {2.73/17 0} Qg5+ {2.67/19 1 (Qe5+)} 36. Ka6 {2.78/19 0} Qxh5
{2.72/20 0} 37. b5 {2.83/19 0} Qe2 {2.83/19 0} 38. Qxh6+ {3.46/19 2} Kg8 {3.46/
1 0} 39. Qd6 {3.52/22 0} Kf7 {3.52/19 0} 40. Kb6 {3.59/23 0} Ke8 {3.66/23 1}
41. Qd5 {3.66/25 0} Ke7 {3.66/23 0 (Qb2)} 42. Kc6 {3.66/22 0} Qg4 {3.40/19 0}
43. Qd6+ {3.29/20 1} Ke8 {3.41/21 0} 44. b6 {3.58/21 0} Qc4+ {3.66/19 0 (Qf3+)}
45. Qc5 {3.41/21 0} Qe4+ {3.58/21 0 (Qe6+)} 46. Kc7 {3.66/23 0 (Qd5)} Qf4+ {3.
35/21 0 (Qh7+)} 47. Kc8 {2.72/21 1 (Qd6)} Qg4+ {3.35/21 0} 48. Kb7 {3.66/21 0}
Qh4 {3.74/20 0} 49. Qd6 {3.61/23 0} Qf2 {3.58/21 0} 50. Kb8 {3.74/21 0} Qb2 {
3.74/22 0 (Qa2)} 51. b7 {3.74/25 0} Qa1 {3.91/22 0 (Qa2)} 52. Qe6+ {7.25/21 1
(Qc5)} Kd8 {3.27/17 0} 53. Qd5+ {2.80/19 0} Ke7 {2.72/13 0} 54. Kc7 {2.50/18 0}
Qc3+ {2.56/12 0 (Qc1+)} 55. Kb6 {7.26/19 1} Qb2+ {7.72/13 0 (Qb4+)} 56. Kc6 {
10.75/15 0} 1-0

[Event "Shootout (Komodo1164-bit, Blitz 1m) "]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "New game"]
[Black "?"]
[Result "1-0"]
[SetUp "1"]
[FEN "8/1p3Qpk/p2q3p/7P/6P1/3K1P2/P1P5/8 w - - 0 1"]
[PlyCount "117"]

1. Kc3 {0.45/18 1} Qe5+ {0.31/21 2} 2. Kd3 {0.43/22 3 (Kb3)} Qd6+ {0.52/20 1}
3. Kc4 {0.54/21 3} Qc6+ {0.63/20 1} 4. Kb3 {0.56/22 1} Qb5+ {0.68/22 4} 5. Ka3
{0.56/19 0} Qc5+ {0.70/20 1} 6. Kb2 {0.71/21 1} Qd4+ {0.72/20 1} 7. Kb3 {0.56/
21 0} Qe3+ {0.57/21 1} 8. Kc4 {0.69/21 1} Qe2+ {0.71/20 1} 9. Kd5 {0.73/20 1}
Qb5+ {0.73/21 2} 10. Kd4 {0.80/21 2} Qb6+ {0.71/21 1} 11. Ke5 {0.77/21 1} Qb2+
{0.74/21 1} 12. Kd6 {0.73/21 1} Qb6+ {0.71/22 1} 13. Kd7 {0.71/22 1} Qc6+ {0.
67/21 1} 14. Kd8 {0.74/21 1} b5 {0.75/21 1} 15. Qf5+ {0.79/22 2} Kh8 {0.80/20 1
} 16. Qc8 {0.92/21 2} Qb6+ {0.92/20 2 (Qd6+)} 17. Kd7+ {1.00/20 1} Kh7 {1.00/
20 0} 18. Qc6 {1.00/19 0} Qa7+ {0.97/21 1} 19. Kd6 {1.00/21 1} Qd4+ {1.00/21 2}
20. Qd5 {1.00/21 1} Qb6+ {1.02/21 1} 21. Kd7 {0.93/21 1} b4 {0.93/21 2} 22. Qe6
{1.02/20 1} Qb7+ {1.02/20 1} 23. Kd6 {1.02/21 1} Qb6+ {1.02/21 1} 24. Kd5 {1.
03/21 1} Qc7 {0.96/21 2 (Qa5+)} 25. Qxa6 {1.68/19 2} Kh8 {1.67/18 1 (Qxc2)} 26.
Qe6 {1.69/21 1} Qa5+ {1.67/22 3 (Qc3)} 27. Kd4 {1.74/23 2} Qa7+ {1.74/23 1} 28.
Kd3 {1.74/24 1} Qa3+ {1.74/23 1 (Qc5)} 29. Qb3 {1.74/19 0} Qa6+ {1.74/21 1} 30.
Qc4 {1.72/22 2} Qd6+ {1.76/23 1} 31. Qd4 {1.76/23 0} Qa6+ {1.76/24 1} 32. Kd2 {
1.77/22 1} Qa5 {1.78/22 1} 33. Kc1 {1.79/22 0 (Kd1)} Qxa2 {1.82/22 0} 34. Qxb4
{1.82/21 0} Qa8 {1.84/21 1 (Qa7)} 35. Qe4 {1.96/21 1} Qa3+ {2.04/21 1} 36. Kd1
{2.16/22 2} Qc3 {2.16/22 1 (Qd6+)} 37. Qd5 {2.18/23 1} Qa1+ {2.18/22 0} 38. Ke2
{2.18/22 0} Qb2 {2.18/23 1 (Qg1)} 39. Qd8+ {2.19/23 1} Kh7 {2.12/5 0} 40. Qd2 {
2.20/21 0 (Qd3+)} Qe5+ {2.22/22 1} 41. Kf1 {2.23/22 0} Qb2 {2.23/20 0} 42. Qd3+
{2.54/22 1} Kh8 {2.55/22 0} 43. Qd8+ {2.55/22 0} Kh7 {2.55/5 0} 44. c4 {2.55/
22 0} Qc1+ {2.55/23 0} 45. Ke2 {2.67/24 2} Qb2+ {2.67/21 0 (Qg1)} 46. Qd2 {2.
67/19 0} Qe5+ {2.68/18 0 (Qb6)} 47. Qe3 {2.68/20 0} Qb2+ {2.68/21 1} 48. Kf1 {
2.71/21 1} Qh2 {2.71/20 0} 49. c5 {2.83/20 1} Qh1+ {2.77/17 0} 50. Ke2 {2.89/
18 0} Qh2+ {2.89/16 0} 51. Kd3 {2.89/18 0} Qb8 {2.95/19 1} 52. c6 {2.96/19 0}
Kh8 {3.08/19 1} 53. Qe6 {3.24/17 0} Qb1+ {3.30/17 0} 54. Kd4 {3.71/16 0} Qb4+ {
3.82/17 1 (Qb8)} 55. Kd5 {4.03/19 0} Qb8 {4.75/17 1} 56. Qd7 {4.90/17 0} Qb3+ {
5.77/18 1} 57. Kc5 {5.92/19 0} Qe3+ {6.73/19 1} 58. Kb5 {7.22/17 0} Qb3+ {7.83/
19 1} 59. Ka6 {7.84/17 0} 1-0

[/pgn]

A quick check with asmFish suggests that 4... Qb2+ is losing in the first game above. The same error occurs in the same position in the second game, on move 11.

Qc5 and Qe3 lose too, and there are no other moves.

check better with your fish.

[Rodolfo Leoni]

Mmmmm, it's not easy to determine whether the queen endgame is winning for white or not. There are many branches.

According to your shootout (thanks a lot for the effort!), white scores 80%, but still it's hard to draw any conclusions, I think. Moreover, the time control is quite short. (These engines can barely figure out a simple pawn endgame in 1 minute )

I just started a test-match with an old Persistent Hash Stockfish version vs. AsmFishW, fixed depth 30, 100 games. This will also be useful to test PH feature a bit better and, hopefully, will confirm Qg2 draw.

I hope to have some interesting results within 2-3 days...

If you want to know if the position is won or not, you can probably put it in FinalGen. I don't know how long that would take, but it's probably a better investment of CPU time.

Thanks Evert,

I need to know how persistent hashes interact with TBs and this position was "ready to use"... I'm finding both qualities and limits of this system. E.g. PHs can't learn the position Michael Byrne posted few days ago, that Mate in 30. Even if I perform a backward analysis score doesn't propagate.... and I can't report this bug!

I'm curious to see their performance with this position.

Rodolfo

[zullil]

Qc5 and Qe3 lose too, and there are no other moves.

check better with your fish.

[d] 8/1p3Qpk/pq5p/4K2P/6P1/5P2/P1P5/8 b - - 12 48

Perhaps there was confusion. In the position above, which I think appeared in both games you posted, Black played Qb2+, which seems to lose (evaluation for White goes above +5).

What's wrong with Qb4, as suggested by asmFish? Or Qc5+ ? Qe3+ is certainly no good.