"Poor Fish": very hard test suite

[peter]

I do not understand the human supplied analysis well enough to know if there can be a contradiction or not.

After 1.(4. at Vincent's? Is it a study starting from earlier position?) Nd7+? Ka5! White has to take 2.Nxb8+ or the evals with full Syzygys get a "Bingo" (128+ with SF, 250 with komodo) at once. After taking the Bishop it's a -#44 according to Lomonosovs

[mcostalba]

Thanks a lot for this precious info!

In this game:

r6r/4k3/p2bP2p/2n2PP1/2BQn2P/1pP1p3/1q1BK3/3R3R b - - bm Qc2; id "hard2016.149"; DBI 2

Variation from Morozevich vs. Vachier-Lagrave, Biel 2009

[Event "Biel International Chess Festival"]
[Site "Biel SUI"]
[Date "2009.07.28"]
[EventDate "2009.07.19"]
[Round "8"]
[Result "0-1"]
[White "Alexander Morozevich"]
[Black "Maxime Vachier-Lagrave"]
[ECO "B80"]
[WhiteElo "2751"]
[BlackElo "2703"]
[PlyCount "152"]

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. f3 e6
7. Be3 b5 8. Qd2 Nbd7 9. g4 h6 10. O-O-O b4 11. Nce2 Qc7
12. h4 d5 13. Nf4 e5 14. Nfe6 fxe6 15. Nxe6 Qa5 16. exd5 Qxa2
17. Qd3 Kf7 18. g5 Nxd5 19. Bh3 Nxe3 20. Nd8+ Ke7 21. Nc6+ Kf7
22. g6+ Kg8 23. Qxe3 Bc5 24. Qe4 Nf8 25. Rd8 Bb7 26. Rxa8 Bxa8
27. h5 Rh7 28. Re1 Bxc6 29. Qxc6 Bd4 30. Kd2 Qxb2 31. Qc4+ Kh8
32. Kd3 a5 33. Qc8 Qa3+ 34. Ke4 b3 35. cxb3 a4 36. Rb1 Qb4
37. Qc4 Qb7+ 38. Qd5 Qb4 39. Qc4 Qd2 40. Bg4 a3 41. Qf7 Qc2+
42. Kd5 Qc5+ 43. Ke4 a2 44. Rc1 a1=Q 45. Rxc5 Bxc5 46. Qd5
Qe1+ 47. Kd3 Qd1+ 48. Kc4 Qxd5+ 49. Kxd5 Ba3 50. Bf5 Kg8
51. Kxe5 Rh8 52. Kd5 Nh7 53. gxh7+ Kf7 54. Bg6+ Kf6 55. f4 Bc1
56. f5 Bd2 57. Kd6 Be1 58. Kd7 Bb4 59. Kc7 Ke5 60. Kd7 Ba3
61. Kc6 Kd4 62. Kc7 Kc3 63. Kd7 Kb4 64. Kd6 Kxb3+ 65. Kd5 Bb2
66. Kd6 Bf6 67. Kc5 Kc3 68. Kd6 Kd4 69. Kc6 Rd8 70. Kb6 Kd5
71. Kc7 Kc5 72. Bf7 g5 73. fxg6 Rd6 74. Be8 Be5 75. Kb7 Rb6+
76. Kc8 Kd6 0-1

I am not able to find Qc2 best move in the PGN, because the only Qc2+ at move 42 refers to a different FEN:

5n1k/5Qpr/6Pp/4p2P/3bK1B1/pP3P2/3q4/1R6 b - - 1 41

See https://en.lichess.org/6aonL8lE#81

[BBauer]

Thank you all for clarifying.
So 1. Nb3 is the only drawing move and the test position is correct.
Computer analysis may still not be enough to solve this very difficult position.
[D]1b6/2p5/1kB5/1PN5/8/3K4/8/q7 w - - 0 1

Kind regards
Bernhard

[Joerg Oster]

I do not understand the human supplied analysis well enough to know if there can be a contradiction or not.

After 1.(4. at Vincent's? Is it a study starting from earlier position?) Nd7+? Ka5! White has to take 2.Nxb8+ or the evals with full Syzygys get a "Bingo" (128+ with SF, 250 with komodo) at once. After taking the Bishop it's a -#44 according to Lomonosovs

And this seems to be really difficult for Stockfish to recognize. Even with the full set of syzygy bases.
Can you provide the full sequence of moves of this -#44, please?

I wonder if there are many zugzwangs involved, or if it needs to avoid the possible KQKBN fortress position. Thanks.

[Lyudmil Tsvetkov]

Hi Marco.

Very nice test!

If I were you, I would collect positions top engines can solve, and not vice-versa, cause I think former ones are considerably less.

For fun sake, try this one, from a simulated game with Louis' SF we played back in November 2014 here on the forum.

[d]1r3r2/4bpkp/1qb1p1p1/3pP1P1/p1pP1Q2/PpP2N1R/1Pn1B2P/3RB2K w - - 0 6

best move Qf6, with mate in 25.

[Joerg Oster]

I do not understand the human supplied analysis well enough to know if there can be a contradiction or not.

After 1.(4. at Vincent's? Is it a study starting from earlier position?) Nd7+? Ka5! White has to take 2.Nxb8+ or the evals with full Syzygys get a "Bingo" (128+ with SF, 250 with komodo) at once. After taking the Bishop it's a -#44 according to Lomonosovs

And this seems to be really difficult for Stockfish to recognize. Even with the full set of syzygy bases.
Can you provide the full sequence of moves of this -#44, please?

I wonder if there are many zugzwangs involved, or if it needs to avoid the possible KQKBN fortress position. Thanks.

Never mind.
I just checked with my phone.

[peter]

Never mind.
I just checked with my phone.

I like this App too very much, mine is for Android and free. Didn't read your first posting before the second one, Jörg

[mcostalba]

Hi Marco.

Very nice test!

If I were you, I would collect positions top engines can solve, and not vice-versa, cause I think former ones are considerably less.

For fun sake, try this one, from a simulated game with Louis' SF we played back in November 2014 here on the forum.

[d]1r3r2/4bpkp/1qb1p1p1/3pP1P1/p1pP1Q2/PpP2N1R/1Pn1B2P/3RB2K w - - 0 6

best move Qf6, with mate in 25.

Thanks Lyudmil,

here is the result of the DBT test (120+120sec 1 thread 512MB hash, 1.2Mnps):

Code: Select all

 +---+---+---+---+---+---+---+---+
 |   | r |   |   |   | r |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   | b | p | k | p |
 +---+---+---+---+---+---+---+---+
 |   | q | b |   | p |   | p |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   | p | P |   | P |   |
 +---+---+---+---+---+---+---+---+
 | p |   | p | P |   | Q |   |   |
 +---+---+---+---+---+---+---+---+
 | P | p | P |   |   | N |   | R |
 +---+---+---+---+---+---+---+---+
 |   | P | n |   | B |   |   | P |
 +---+---+---+---+---+---+---+---+
 |   |   |   | R | B |   |   | K |
 +---+---+---+---+---+---+---+---+

Fen: 1r3r2/4bpkp/1qb1p1p1/3pP1P1/p1pP1Q2/PpP2N1R/1Pn1B2P/3RB2K w - - 0 6
Key: 56062F5662BB9942
Checkers: 

Warm-up best move: Rh6, score: cp -184
Forcing best move: Qf6+
After forcing best move, score: cp -89

So I am sorry but test failed, your position if strong (engine failed to find bm in normal search), but not so strong.

[peter]

In this game:

r6r/4k3/p2bP2p/2n2PP1/2BQn2P/1pP1p3/1q1BK3/3R3R b - - bm Qc2; id "hard2016.149"; DBI 2

Variation from Morozevich vs. Vachier-Lagrave, Biel 2009

[Event "Biel International Chess Festival"]
[Site "Biel SUI"]
[Date "2009.07.28"]
[EventDate "2009.07.19"]
[Round "8"]
[Result "0-1"]
[White "Alexander Morozevich"]
[Black "Maxime Vachier-Lagrave"]
[ECO "B80"]
[WhiteElo "2751"]
[BlackElo "2703"]
[PlyCount "152"]

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. f3 e6
7. Be3 b5 8. Qd2 Nbd7 9. g4 h6 10. O-O-O b4 11. Nce2 Qc7
12. h4 d5 13. Nf4 e5 14. Nfe6 fxe6 15. Nxe6 Qa5 16. exd5 Qxa2
17. Qd3 Kf7 18. g5 Nxd5 19. Bh3 Nxe3 20. Nd8+ Ke7 21. Nc6+ Kf7
22. g6+ Kg8 23. Qxe3 Bc5 24. Qe4 Nf8 25. Rd8 Bb7 26. Rxa8 Bxa8
27. h5 Rh7 28. Re1 Bxc6 29. Qxc6 Bd4 30. Kd2 Qxb2 31. Qc4+ Kh8
32. Kd3 a5 33. Qc8 Qa3+ 34. Ke4 b3 35. cxb3 a4 36. Rb1 Qb4
37. Qc4 Qb7+ 38. Qd5 Qb4 39. Qc4 Qd2 40. Bg4 a3 41. Qf7 Qc2+
42. Kd5 Qc5+ 43. Ke4 a2 44. Rc1 a1=Q 45. Rxc5 Bxc5 46. Qd5
Qe1+ 47. Kd3 Qd1+ 48. Kc4 Qxd5+ 49. Kxd5 Ba3 50. Bf5 Kg8
51. Kxe5 Rh8 52. Kd5 Nh7 53. gxh7+ Kf7 54. Bg6+ Kf6 55. f4 Bc1
56. f5 Bd2 57. Kd6 Be1 58. Kd7 Bb4 59. Kc7 Ke5 60. Kd7 Ba3
61. Kc6 Kd4 62. Kc7 Kc3 63. Kd7 Kb4 64. Kd6 Kxb3+ 65. Kd5 Bb2
66. Kd6 Bf6 67. Kc5 Kc3 68. Kd6 Kd4 69. Kc6 Rd8 70. Kb6 Kd5
71. Kc7 Kc5 72. Bf7 g5 73. fxg6 Rd6 74. Be8 Be5 75. Kb7 Rb6+
76. Kc8 Kd6 0-1

I am not able to find Qc2 best move in the PGN, because the only Qc2+ at move 42 refers to a different FEN:

5n1k/5Qpr/6Pp/4p2P/3bK1B1/pP3P2/3q4/1R6 b - - 1 41

I think the test- position is from another game Moro-Lagrave, I have it in my database only from the fen onwards and the year in my .pgn is 2012. I think I stored it after one of Anton Stadlhofer's postings at CSS- Forum he used to bring up there from time to time more or less regularly under the title "Harte Nuss", and as far as I remember there was a collection of those to download from Arena- hp once

[Vinvin]

Thanks a lot for this precious info!

In this game:

r6r/4k3/p2bP2p/2n2PP1/2BQn2P/1pP1p3/1q1BK3/3R3R b - - bm Qc2; id "hard2016.149"; DBI 2

Variation from Morozevich vs. Vachier-Lagrave, Biel 2009
...

I am not able to find Qc2 best move in the PGN, because the only Qc2+ at move 42 refers to a different FEN:

5n1k/5Qpr/6Pp/4p2P/3bK1B1/pP3P2/3q4/1R6 b - - 1 41

See https://en.lichess.org/6aonL8lE#81

It's a variation, so probably someone who analyzed.
Here you can see Chessexplained analyzing positions very close : https://youtu.be/i6KLpOgACWQ?t=13m25s