Is there anymore unsolved positions at all!?

[jp]

This one comes to mind:

[d]rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

This is not a good position.

A good position is a position when you are convinced that all top engines (including special engines to solve problems) fail to find the right move.

Jokes aside, it's only not good to test engines with because the test-giver doesn't know the solution.

So good positions are any number of endgame TB positions that no engines without TBs have been able to solve (sometimes even with (N-1)-man TBs).

[MikeB]

Opening position is solved already: DRAW. Only 1.g4?? loses.

Not all the time ...
[pgn][Event "?"]
[Site "C:/cluster.mfb/pgn"]
[Date "2020.08.21"]
[Round "?"]
[White "Honey-XIr5"]
[Black "stockfish_11"]
[Result "1-0"]
[FEN "rnbqkbnr/pppppppp/8/8/6P1/8/PPPPPP1P/RNBQKBNR b KQkq - 0 1"]
[GameDuration "00:03:57"]
[GameEndTime "2020-08-21T01:40:34.418 Eastern Daylight Time"]
[GameStartTime "2020-08-21T01:36:36.955 Eastern Daylight Time"]
[PlyCount "121"]
[SetUp "1"]
[Termination "adjudication"]
[TimeControl "60+1"]

1... d5 {+1.46/20 1.8s} 2. g5 {-0.60/24 11s} e5 {+1.60/20 1.5s}
3. d4 {-0.56/21 0.89s} exd4 {+1.73/20 0.99s} 4. Nf3 {-0.64/23 5.1s}
c5 {+1.84/21 1.1s} 5. c3 {-0.62/22 1.2s} dxc3 {+1.69/21 1.8s}
6. Nxc3 {-0.59/20 1.5s} d4 {+1.71/24 5.7s} 7. Ne4 {-0.66/20 1.4s}
Nc6 {+1.23/25 8.1s} 8. Bg2 {-0.69/19 1.5s} Bf5 {+1.32/20 1.5s}
9. Ng3 {-0.64/21 2.0s} Be6 {+1.46/20 0.82s} 10. e3 {-0.69/20 1.3s}
d3 {+1.50/18 1.1s} 11. O-O {-0.38/21 3.2s} h6 {+1.68/19 1.0s}
12. g6 {-0.43/19 0.76s} a6 {+0.61/25 14s} 13. gxf7+ {-0.22/22 2.7s}
Bxf7 {+0.77/23 1.1s} 14. b3 {-0.32/20 1.2s} Qd7 {+0.32/22 1.9s}
15. Ba3 {-0.27/22 1.6s} Rd8 {+0.38/25 5.1s} 16. Qc1 {0.00/21 2.2s}
Nf6 {+0.53/21 1.4s} 17. Bxc5 {-0.09/22 1.5s} Be7 {+0.38/21 1.2s}
18. Qa3 {0.00/23 2.4s} h5 {0.00/25 7.2s} 19. Ng5 {-0.09/26 4.3s}
Bg6 {+0.34/22 1.1s} 20. Bxc6 {+0.27/23 1.6s} bxc6 {+0.13/23 1.3s}
21. h4 {+0.26/24 1.7s} Bxc5 {+0.11/24 1.2s} 22. Qxc5 {+0.17/26 3.2s}
Qd5 {0.00/25 1.8s} 23. Qxd5 {+0.19/23 1.0s} cxd5 {0.00/23 1.2s}
24. Rac1 {+0.11/24 1.8s} Ke7 {0.00/26 1.7s} 25. Rc7+ {+0.30/23 1.6s}
Rd7 {0.00/26 1.7s} 26. Rc5 {+0.25/23 1.4s} Re8 {-0.01/23 0.81s}
27. Rd1 {+0.29/24 1.5s} Rd6 {0.00/24 0.77s} 28. f3 {+0.43/22 1.4s}
Nd7 {-0.39/28 11s} 29. Rc7 {+0.41/20 1.4s} Kf8 {-0.44/23 0.46s}
30. Nf1 {+0.61/20 1.2s} Ne5 {-0.35/22 0.80s} 31. Rdc1 {+0.47/23 4.4s}
Re7 {-0.44/25 4.3s} 32. Kf2 {+0.50/20 1.1s} a5 {-0.23/22 0.45s}
33. R7c5 {+0.42/24 4.0s} a4 {-0.42/22 1.5s} 34. Ra5 {+0.52/20 0.77s}
axb3 {-0.25/21 0.83s} 35. axb3 {+0.51/23 2.7s} Re8 {-0.27/23 2.2s}
36. Rc7 {+0.41/24 2.3s} Rf6 {-0.22/21 0.54s} 37. Kg3 {+0.42/23 1.6s}
Rd6 {-0.29/23 1.4s} 38. Raa7 {+0.58/24 3.7s} Rf6 {-0.16/23 0.63s}
39. Rxg7 {+0.67/22 0.96s} Nc6 {-0.76/27 3.4s} 40. Rad7 {+0.61/23 1.9s}
Ne7 {-0.84/24 0.64s} 41. Rgxe7 {+0.50/26 1.9s} Rxe7 {-0.54/23 1.1s}
42. Rxd5 {+0.63/23 1.3s} Be8 {-0.77/23 0.91s} 43. e4 {+1.15/23 1.9s}
Rc6 {-0.86/24 1.6s} 44. Rxd3 {+1.37/24 0.74s} Rd7 {-0.57/23 0.48s}
45. Rxd7 {+1.43/24 0.91s} Bxd7 {-0.54/23 0.93s} 46. Kf4 {+1.61/25 1.7s}
Be8 {-0.53/21 0.65s} 47. Ke5 {+1.80/23 1.9s} Bf7 {-0.80/23 1.2s}
48. Nd2 {+1.03/26 6.8s} Rc2 {-1.06/23 1.8s} 49. Kf6 {+1.77/21 0.60s}
Rc6+ {-1.90/24 1.9s} 50. Kf5 {+2.29/22 0.94s} Rc2 {-2.30/24 2.5s}
51. Nc4 {+2.83/21 0.74s} Rh2 {-2.42/23 0.92s} 52. Nxf7 {+3.67/24 0.87s}
Kxf7 {-2.09/22 0.59s} 53. Kg5 {+3.51/23 0.91s} Ke6 {-3.42/25 1.9s}
54. Kxh5 {+4.42/24 1.00s} Re2 {-2.64/26 1.0s} 55. Kg4 {+4.78/24 1.7s}
Rg2+ {-4.27/24 1.0s} 56. Kf4 {+5.39/23 0.57s} Rh2 {-3.40/25 0.71s}
57. b4 {+5.88/23 0.67s} Rh1 {-3.30/24 1.3s} 58. Nb2 {+6.28/22 0.80s}
Kf6 {-3.83/22 1.00s} 59. Nd3 {+6.36/21 0.83s} Rh3 {-4.50/23 1.0s}
60. e5+ {+7.68/22 1.9s} Kf7 {-6.00/20 1.0s} 61. Ke4 {+7.78/24 1.1s}
Rh2 {-7.87/20 1.0s, White wins by adjudication} 1-0[/pgn]

[Vinvin]

[d]4q1kn/2Bp1p2/1N1PpPp1/1P2P1P1/2N3b1/6p1/1P4Pb/7K w - - 0 1

If the best move is all that is needed, then there seems to be a "lot" of best moves.

I took "best" to mean "key". Have you followed perejaslav's link to the discussion of this study?

I assume many engines will find the initial key sequence, and then get stuck for a long time at 0.00. Like here.

info depth 127 seldepth 41 multipv 1 score cp 0 nodes 1930533338907 nps 63402350 hashfull 1000 tbhits 0 time 30448924 pv c4a5 g4e2 a5b7 e2b5 b7d8 b5e2 b2b4 e2b5 b6c8 b5c6 c8a7 g8h7 c7b6 e8g8 b6a5 c6a8 a5c7 a8d5 b4b5 d5b7 b5b6 b7a6 a7b5 a6b5 b6b7 g8e8 b7b8q b5c4 b8b4 c4d5 b4h4 h7g8 h4h6 e8f8 h6h3 f8e8 h3h4 e8f8 c7b6 f8e8

Here's the winning idea :

[pgn][Event "Computer Chess Test Suite"]
[Site "EPD2diag V1.5"]
[Date "2020.01.27"]
[White "Hard-Talkchess-2020.077"]
[Black "Na5"]
[Result "1-0"]
[FEN "4q1kn/2Bp1p2/1N1PpPp1/1P2P1P1/2N3b1/6p1/1P4Pb/7K w - - 0 1"]
[SetUp "1"]

1. Na5 Be2 2. Nb7 Bd3 3. Nd8 Bxb5 4. b3 Qf8 5. Na4 Kh7 6. Nc3 Bf1 7. b4 Bd3 8. b5 Bxb5 9. Nxb5 Qe8 10. Nd4 Kg8 11. Nf3 Kh7 12. Nxh2 gxh2 13. Kxh2 Kg8 14. Kg3 Kh7 15. Kf3 Kg8 16. Ke4 Kh7 17. Kd4 Kg8 18. Kc5 Kh7 19. Kb6 Kg8 20. Kb7 Kh7 21. Bb6 Kg8 22. Nc6 Kh7 23. Nb8 Kg8 24. Kc7 Kh7 25. Nxd7 1-0[/pgn]

It's not simple to me how white wins afterward.

Is it not clear ?
The d pawn is going to promote.
This is possible because the black is defenseless : the king, the queen and the knight are trapped in a little box.

[h1a8]

[d]4q1kn/2Bp1p2/1N1PpPp1/1P2P1P1/2N3b1/6p1/1P4Pb/7K w - - 0 1

If the best move is all that is needed, then there seems to be a "lot" of best moves.

I took "best" to mean "key". Have you followed perejaslav's link to the discussion of this study?

I assume many engines will find the initial key sequence, and then get stuck for a long time at 0.00. Like here.

info depth 127 seldepth 41 multipv 1 score cp 0 nodes 1930533338907 nps 63402350 hashfull 1000 tbhits 0 time 30448924 pv c4a5 g4e2 a5b7 e2b5 b7d8 b5e2 b2b4 e2b5 b6c8 b5c6 c8a7 g8h7 c7b6 e8g8 b6a5 c6a8 a5c7 a8d5 b4b5 d5b7 b5b6 b7a6 a7b5 a6b5 b6b7 g8e8 b7b8q b5c4 b8b4 c4d5 b4h4 h7g8 h4h6 e8f8 h6h3 f8e8 h3h4 e8f8 c7b6 f8e8

Here's the winning idea :

[pgn][Event "Computer Chess Test Suite"]
[Site "EPD2diag V1.5"]
[Date "2020.01.27"]
[White "Hard-Talkchess-2020.077"]
[Black "Na5"]
[Result "1-0"]
[FEN "4q1kn/2Bp1p2/1N1PpPp1/1P2P1P1/2N3b1/6p1/1P4Pb/7K w - - 0 1"]
[SetUp "1"]

1. Na5 Be2 2. Nb7 Bd3 3. Nd8 Bxb5 4. b3 Qf8 5. Na4 Kh7 6. Nc3 Bf1 7. b4 Bd3 8. b5 Bxb5 9. Nxb5 Qe8 10. Nd4 Kg8 11. Nf3 Kh7 12. Nxh2 gxh2 13. Kxh2 Kg8 14. Kg3 Kh7 15. Kf3 Kg8 16. Ke4 Kh7 17. Kd4 Kg8 18. Kc5 Kh7 19. Kb6 Kg8 20. Kb7 Kh7 21. Bb6 Kg8 22. Nc6 Kh7 23. Nb8 Kg8 24. Kc7 Kh7 25. Nxd7 1-0[/pgn]

It's not simple to me how white wins afterward.

Is it not clear ?
The d pawn is going to promote.
This is possible because the black is defenseless : the king, the queen and the knight are trapped in a little box.

I played the cpu at least 5 times. Every time there is a wrinkle that makes the game a draw. I go over these games and find there is subtle hidden techniques that need to be done in some lines.
I challenge you to play the cpu (strongest stockfish available) 5 times from the starting position of this puzzle (5 min games). Tell me how you fare.

[Vinvin]

[d]4q1kn/2Bp1p2/1N1PpPp1/1P2P1P1/2N3b1/6p1/1P4Pb/7K w - - 0 1

If the best move is all that is needed, then there seems to be a "lot" of best moves.

I took "best" to mean "key". Have you followed perejaslav's link to the discussion of this study?

I assume many engines will find the initial key sequence, and then get stuck for a long time at 0.00. Like here.

info depth 127 seldepth 41 multipv 1 score cp 0 nodes 1930533338907 nps 63402350 hashfull 1000 tbhits 0 time 30448924 pv c4a5 g4e2 a5b7 e2b5 b7d8 b5e2 b2b4 e2b5 b6c8 b5c6 c8a7 g8h7 c7b6 e8g8 b6a5 c6a8 a5c7 a8d5 b4b5 d5b7 b5b6 b7a6 a7b5 a6b5 b6b7 g8e8 b7b8q b5c4 b8b4 c4d5 b4h4 h7g8 h4h6 e8f8 h6h3 f8e8 h3h4 e8f8 c7b6 f8e8

Here's the winning idea :

[pgn][Event "Computer Chess Test Suite"]
[Site "EPD2diag V1.5"]
[Date "2020.01.27"]
[White "Hard-Talkchess-2020.077"]
[Black "Na5"]
[Result "1-0"]
[FEN "4q1kn/2Bp1p2/1N1PpPp1/1P2P1P1/2N3b1/6p1/1P4Pb/7K w - - 0 1"]
[SetUp "1"]

1. Na5 Be2 2. Nb7 Bd3 3. Nd8 Bxb5 4. b3 Qf8 5. Na4 Kh7 6. Nc3 Bf1 7. b4 Bd3 8. b5 Bxb5 9. Nxb5 Qe8 10. Nd4 Kg8 11. Nf3 Kh7 12. Nxh2 gxh2 13. Kxh2 Kg8 14. Kg3 Kh7 15. Kf3 Kg8 16. Ke4 Kh7 17. Kd4 Kg8 18. Kc5 Kh7 19. Kb6 Kg8 20. Kb7 Kh7 21. Bb6 Kg8 22. Nc6 Kh7 23. Nb8 Kg8 24. Kc7 Kh7 25. Nxd7 1-0[/pgn]

It's not simple to me how white wins afterward.

Is it not clear ?
The d pawn is going to promote.
This is possible because the black is defenseless : the king, the queen and the knight are trapped in a little box.

I played the cpu at least 5 times. Every time there is a wrinkle that makes the game a draw. I go over these games and find there is subtle hidden techniques that need to be done in some lines.
I challenge you to play the cpu (strongest stockfish available) 5 times from the starting position of this puzzle (5 min games). Tell me how you fare.

Is it really important to know how a human would perform in 5 minutes in this study ?
The plan in 4 steps :
1) close the box with Na5-b7-d8
2) wins the white square bishop by pushing the b pawn supported by the knight
3) take the b2 bishop with the knight
4) bring the king to the d7 pawn and take it to queen the d6 pawn

Here's the eval from SF after 1.Na5!
7 best moves after some learning :

Code: Select all

FEN: 4q1kn/2Bp1p2/1N1PpPp1/NP2P1P1/6b1/6p1/1P4Pb/7K b - - 1 1

Stockfish_20080923_x64_modern:
...
 36/41	00:44	 573 418 706	12 802 668	+4,13	1. ... Kf8 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Kg8 5.Na4 Bc6 6.Nc3 Bb7 7.b4 Bd5 8.b5 Bc6 9.Ba5 Ba8 10.Na4 Kh7 11.Bb6 Qg8 12.Bc7 Bd5 13.Nc5 Qe8 14.b6 Bc6 15.b7 Bxb7 16.Ncxb7 Qf8 17.Nc5 Qe8 18.Nb3 Qg8 19.Bb6 Qe8 20.Nd2 Qg8 21.Nf1 Qf8
 37/71	00:44	 573 418 706	12 802 668	+4,51	1. ... Kh7 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Bf1 5.Na4 Qf8 6.Bb6 Bd3 7.Nc3 Ba6 8.Bc7 Bf1 9.Ba5 Kg8 10.Bb6 Ba6 11.Bc7 Bb7 12.b4 Bc6 13.Bb6 Kh7 14.Ba5 Qe8 15.Bc7 Bd5 16.b5 Ba8 17.b6 Bc6 18.Na2 Kg8 19.Nc1 Be4 20.Nb3 Bd5 21.Na5 Ba2 22.b7 Kf8 23.b8R Bd5 24.Nab7 Kg8 25.Bb6 Qf8
 37/59	00:44	 573 418 706	12 802 668	+4,11	1. ... Qf8 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Bf1 5.Na4 Bd3 6.Nc3 Qh6 7.gxh6 g5 8.Bb6 Ng6 9.h7+ Kxh7 10.Nxf7 Kg8 11.Nh6+ Kh7 12.Ng4 Bf5 13.Nxh2 gxh2 14.Bd4 Nf4 15.Kxh2 Bd3 16.Bf2 g4 17.g3 Ne2 18.Nxe2 Bxe2 19.Be3 Kg6 20.Kg2 Ba6 21.b4 Kf7 22.Kg1
 37/68	00:44	 573 418 706	12 802 668	+3,88	1. ... Bf5 2.Nb7 Bd3 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bg5 Bc6 34.Bf6+ Kg8 35.Bd4
 37/67	00:44	 573 418 706	12 802 668	+3,88	1. ... Bd1 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bg5 Bc6 34.Bf6+ Kg8
 37/71	00:44	 573 418 706	12 802 668	+3,88	1. ... Bh5 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bc3+ Kg8 34.Bd4 Bb7 35.Kf6 Bc6 36.Be3 Bb7
 37/68	00:44	 573 418 706	12 802 668	+3,88	1. ... Be2 2.Nb7 Bc4 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bc3+ Kg8 34.Bd4 Bb7

[h1a8]

[d]4q1kn/2Bp1p2/1N1PpPp1/1P2P1P1/2N3b1/6p1/1P4Pb/7K w - - 0 1

If the best move is all that is needed, then there seems to be a "lot" of best moves.

I took "best" to mean "key". Have you followed perejaslav's link to the discussion of this study?

I assume many engines will find the initial key sequence, and then get stuck for a long time at 0.00. Like here.

info depth 127 seldepth 41 multipv 1 score cp 0 nodes 1930533338907 nps 63402350 hashfull 1000 tbhits 0 time 30448924 pv c4a5 g4e2 a5b7 e2b5 b7d8 b5e2 b2b4 e2b5 b6c8 b5c6 c8a7 g8h7 c7b6 e8g8 b6a5 c6a8 a5c7 a8d5 b4b5 d5b7 b5b6 b7a6 a7b5 a6b5 b6b7 g8e8 b7b8q b5c4 b8b4 c4d5 b4h4 h7g8 h4h6 e8f8 h6h3 f8e8 h3h4 e8f8 c7b6 f8e8

Here's the winning idea :

[pgn][Event "Computer Chess Test Suite"]
[Site "EPD2diag V1.5"]
[Date "2020.01.27"]
[White "Hard-Talkchess-2020.077"]
[Black "Na5"]
[Result "1-0"]
[FEN "4q1kn/2Bp1p2/1N1PpPp1/1P2P1P1/2N3b1/6p1/1P4Pb/7K w - - 0 1"]
[SetUp "1"]

1. Na5 Be2 2. Nb7 Bd3 3. Nd8 Bxb5 4. b3 Qf8 5. Na4 Kh7 6. Nc3 Bf1 7. b4 Bd3 8. b5 Bxb5 9. Nxb5 Qe8 10. Nd4 Kg8 11. Nf3 Kh7 12. Nxh2 gxh2 13. Kxh2 Kg8 14. Kg3 Kh7 15. Kf3 Kg8 16. Ke4 Kh7 17. Kd4 Kg8 18. Kc5 Kh7 19. Kb6 Kg8 20. Kb7 Kh7 21. Bb6 Kg8 22. Nc6 Kh7 23. Nb8 Kg8 24. Kc7 Kh7 25. Nxd7 1-0[/pgn]

It's not simple to me how white wins afterward.

Is it not clear ?
The d pawn is going to promote.
This is possible because the black is defenseless : the king, the queen and the knight are trapped in a little box.

I played the cpu at least 5 times. Every time there is a wrinkle that makes the game a draw. I go over these games and find there is subtle hidden techniques that need to be done in some lines.
I challenge you to play the cpu (strongest stockfish available) 5 times from the starting position of this puzzle (5 min games). Tell me how you fare.

Is it really important to know how a human would perform in 5 minutes in this study ?
The plan in 4 steps :
1) close the box with Na5-b7-d8
2) wins the white square bishop by pushing the b pawn supported by the knight
3) take the b2 bishop with the knight
4) bring the king to the d7 pawn and take it to queen the d6 pawn

Here's the eval from SF after 1.Na5!
7 best moves after some learning :

Code: Select all

FEN: 4q1kn/2Bp1p2/1N1PpPp1/NP2P1P1/6b1/6p1/1P4Pb/7K b - - 1 1

Stockfish_20080923_x64_modern:
...
 36/41	00:44	 573 418 706	12 802 668	+4,13	1. ... Kf8 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Kg8 5.Na4 Bc6 6.Nc3 Bb7 7.b4 Bd5 8.b5 Bc6 9.Ba5 Ba8 10.Na4 Kh7 11.Bb6 Qg8 12.Bc7 Bd5 13.Nc5 Qe8 14.b6 Bc6 15.b7 Bxb7 16.Ncxb7 Qf8 17.Nc5 Qe8 18.Nb3 Qg8 19.Bb6 Qe8 20.Nd2 Qg8 21.Nf1 Qf8
 37/71	00:44	 573 418 706	12 802 668	+4,51	1. ... Kh7 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Bf1 5.Na4 Qf8 6.Bb6 Bd3 7.Nc3 Ba6 8.Bc7 Bf1 9.Ba5 Kg8 10.Bb6 Ba6 11.Bc7 Bb7 12.b4 Bc6 13.Bb6 Kh7 14.Ba5 Qe8 15.Bc7 Bd5 16.b5 Ba8 17.b6 Bc6 18.Na2 Kg8 19.Nc1 Be4 20.Nb3 Bd5 21.Na5 Ba2 22.b7 Kf8 23.b8R Bd5 24.Nab7 Kg8 25.Bb6 Qf8
 37/59	00:44	 573 418 706	12 802 668	+4,11	1. ... Qf8 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Bf1 5.Na4 Bd3 6.Nc3 Qh6 7.gxh6 g5 8.Bb6 Ng6 9.h7+ Kxh7 10.Nxf7 Kg8 11.Nh6+ Kh7 12.Ng4 Bf5 13.Nxh2 gxh2 14.Bd4 Nf4 15.Kxh2 Bd3 16.Bf2 g4 17.g3 Ne2 18.Nxe2 Bxe2 19.Be3 Kg6 20.Kg2 Ba6 21.b4 Kf7 22.Kg1
 37/68	00:44	 573 418 706	12 802 668	+3,88	1. ... Bf5 2.Nb7 Bd3 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bg5 Bc6 34.Bf6+ Kg8 35.Bd4
 37/67	00:44	 573 418 706	12 802 668	+3,88	1. ... Bd1 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bg5 Bc6 34.Bf6+ Kg8
 37/71	00:44	 573 418 706	12 802 668	+3,88	1. ... Bh5 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bc3+ Kg8 34.Bd4 Bb7 35.Kf6 Bc6 36.Be3 Bb7
 37/68	00:44	 573 418 706	12 802 668	+3,88	1. ... Be2 2.Nb7 Bc4 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bc3+ Kg8 34.Bd4 Bb7

I knew all that before I even played the cpu once. All that can be easily achieved blindfolded. The problem comes after the king gets to d7. In some cases it depends on where blacks king and queen are before you move the knight, otherwise it is a draw. There are other wrinkles as well. That's why I ask you to play stockfish 5 times and you will see for yourself. It's not as easy as you think. I did everything correctly and got king to d7 on my very first attempt. So that's not a problem at all.

[zullil]

[d]4q1kn/2Bp1p2/1N1PpPp1/1P2P1P1/2N3b1/6p1/1P4Pb/7K w - - 0 1

If the best move is all that is needed, then there seems to be a "lot" of best moves.

I took "best" to mean "key". Have you followed perejaslav's link to the discussion of this study?

I assume many engines will find the initial key sequence, and then get stuck for a long time at 0.00. Like here.

info depth 127 seldepth 41 multipv 1 score cp 0 nodes 1930533338907 nps 63402350 hashfull 1000 tbhits 0 time 30448924 pv c4a5 g4e2 a5b7 e2b5 b7d8 b5e2 b2b4 e2b5 b6c8 b5c6 c8a7 g8h7 c7b6 e8g8 b6a5 c6a8 a5c7 a8d5 b4b5 d5b7 b5b6 b7a6 a7b5 a6b5 b6b7 g8e8 b7b8q b5c4 b8b4 c4d5 b4h4 h7g8 h4h6 e8f8 h6h3 f8e8 h3h4 e8f8 c7b6 f8e8

Here's the winning idea :

[pgn][Event "Computer Chess Test Suite"]
[Site "EPD2diag V1.5"]
[Date "2020.01.27"]
[White "Hard-Talkchess-2020.077"]
[Black "Na5"]
[Result "1-0"]
[FEN "4q1kn/2Bp1p2/1N1PpPp1/1P2P1P1/2N3b1/6p1/1P4Pb/7K w - - 0 1"]
[SetUp "1"]

1. Na5 Be2 2. Nb7 Bd3 3. Nd8 Bxb5 4. b3 Qf8 5. Na4 Kh7 6. Nc3 Bf1 7. b4 Bd3 8. b5 Bxb5 9. Nxb5 Qe8 10. Nd4 Kg8 11. Nf3 Kh7 12. Nxh2 gxh2 13. Kxh2 Kg8 14. Kg3 Kh7 15. Kf3 Kg8 16. Ke4 Kh7 17. Kd4 Kg8 18. Kc5 Kh7 19. Kb6 Kg8 20. Kb7 Kh7 21. Bb6 Kg8 22. Nc6 Kh7 23. Nb8 Kg8 24. Kc7 Kh7 25. Nxd7 1-0[/pgn]

It's not simple to me how white wins afterward.

Is it not clear ?
The d pawn is going to promote.
This is possible because the black is defenseless : the king, the queen and the knight are trapped in a little box.

I played the cpu at least 5 times. Every time there is a wrinkle that makes the game a draw. I go over these games and find there is subtle hidden techniques that need to be done in some lines.
I challenge you to play the cpu (strongest stockfish available) 5 times from the starting position of this puzzle (5 min games). Tell me how you fare.

Is it really important to know how a human would perform in 5 minutes in this study ?
The plan in 4 steps :
1) close the box with Na5-b7-d8
2) wins the white square bishop by pushing the b pawn supported by the knight
3) take the b2 bishop with the knight
4) bring the king to the d7 pawn and take it to queen the d6 pawn

Here's the eval from SF after 1.Na5!
7 best moves after some learning :

Code: Select all

FEN: 4q1kn/2Bp1p2/1N1PpPp1/NP2P1P1/6b1/6p1/1P4Pb/7K b - - 1 1

Stockfish_20080923_x64_modern:
...
 36/41	00:44	 573 418 706	12 802 668	+4,13	1. ... Kf8 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Kg8 5.Na4 Bc6 6.Nc3 Bb7 7.b4 Bd5 8.b5 Bc6 9.Ba5 Ba8 10.Na4 Kh7 11.Bb6 Qg8 12.Bc7 Bd5 13.Nc5 Qe8 14.b6 Bc6 15.b7 Bxb7 16.Ncxb7 Qf8 17.Nc5 Qe8 18.Nb3 Qg8 19.Bb6 Qe8 20.Nd2 Qg8 21.Nf1 Qf8
 37/71	00:44	 573 418 706	12 802 668	+4,51	1. ... Kh7 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Bf1 5.Na4 Qf8 6.Bb6 Bd3 7.Nc3 Ba6 8.Bc7 Bf1 9.Ba5 Kg8 10.Bb6 Ba6 11.Bc7 Bb7 12.b4 Bc6 13.Bb6 Kh7 14.Ba5 Qe8 15.Bc7 Bd5 16.b5 Ba8 17.b6 Bc6 18.Na2 Kg8 19.Nc1 Be4 20.Nb3 Bd5 21.Na5 Ba2 22.b7 Kf8 23.b8R Bd5 24.Nab7 Kg8 25.Bb6 Qf8
 37/59	00:44	 573 418 706	12 802 668	+4,11	1. ... Qf8 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Bf1 5.Na4 Bd3 6.Nc3 Qh6 7.gxh6 g5 8.Bb6 Ng6 9.h7+ Kxh7 10.Nxf7 Kg8 11.Nh6+ Kh7 12.Ng4 Bf5 13.Nxh2 gxh2 14.Bd4 Nf4 15.Kxh2 Bd3 16.Bf2 g4 17.g3 Ne2 18.Nxe2 Bxe2 19.Be3 Kg6 20.Kg2 Ba6 21.b4 Kf7 22.Kg1
 37/68	00:44	 573 418 706	12 802 668	+3,88	1. ... Bf5 2.Nb7 Bd3 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bg5 Bc6 34.Bf6+ Kg8 35.Bd4
 37/67	00:44	 573 418 706	12 802 668	+3,88	1. ... Bd1 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bg5 Bc6 34.Bf6+ Kg8
 37/71	00:44	 573 418 706	12 802 668	+3,88	1. ... Bh5 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bc3+ Kg8 34.Bd4 Bb7 35.Kf6 Bc6 36.Be3 Bb7
 37/68	00:44	 573 418 706	12 802 668	+3,88	1. ... Be2 2.Nb7 Bc4 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bc3+ Kg8 34.Bd4 Bb7

I knew all that before I even played the cpu once. All that can be easily achieved blindfolded. The problem comes after the king gets to d7. In some cases it depends on where blacks king and queen are before you move the knight, otherwise it is a draw. There are other wrinkles as well. That's why I ask you to play stockfish 5 times and you will see for yourself. It's not as easy as you think. I did everything correctly and got king to d7 on my very first attempt. So that's not a problem at all.

Have you seen the analysis presented by the composer?

https://glarean-magazin.ch/2019/01/19/m ... lemschach/

[drewdrew]

[d]4q1kn/2Bp1p2/1N1PpPp1/1P2P1P1/2N3b1/6p1/1P4Pb/7K w - - 0 1

If the best move is all that is needed, then there seems to be a "lot" of best moves.

I took "best" to mean "key". Have you followed perejaslav's link to the discussion of this study?

I assume many engines will find the initial key sequence, and then get stuck for a long time at 0.00. Like here.

info depth 127 seldepth 41 multipv 1 score cp 0 nodes 1930533338907 nps 63402350 hashfull 1000 tbhits 0 time 30448924 pv c4a5 g4e2 a5b7 e2b5 b7d8 b5e2 b2b4 e2b5 b6c8 b5c6 c8a7 g8h7 c7b6 e8g8 b6a5 c6a8 a5c7 a8d5 b4b5 d5b7 b5b6 b7a6 a7b5 a6b5 b6b7 g8e8 b7b8q b5c4 b8b4 c4d5 b4h4 h7g8 h4h6 e8f8 h6h3 f8e8 h3h4 e8f8 c7b6 f8e8

After a (long) while I get:
info depth 111 seldepth 40 multipv 1 score cp 0 nodes 4802448924330 nps 395357553 hashfull 468 tbhits 5121581803 time 12147103 pv c4a5 g8h7 a5b7 g4e2 b7d8 e2b5 b6c8 b5a6 c8a7 e8g8 b2b3 g8e8 b3b4 a6b7 c7a5 b7a8 b4b5 h7g8 a5c7 a8d5 b5b6 d5e4 a7b5 g8h7 b5c3 e4c6 c3e2 c6d5 e2f4 d5e4 f4d3 e4d3 b6b7 d3c4 b7b8q e8f8 c7b6 f8e8
info depth 112 currmove c4a5 currmovenumber 1
info depth 112 seldepth 50 multipv 1 score cp 8 lowerbound nodes 17005964673455 nps 416383688 hashfull 574 tbhits 19875148207 time 40842053 pv c4a5
info depth 111 currmove c4a5 currmovenumber 1
info depth 112 seldepth 50 multipv 1 score cp 16 lowerbound nodes 17015768413244 nps 416405432 hashfull 574 tbhits 19885266638 time 40863464 pv c4a5

This iteration is taking a very long time though...

Would be interesting to see the next PV ... if/when it arrives.

Unfortunately, I waited for a while and no further output came.
I got tired of it and decided to stop the search. I then re-started the search, keeping whatever was in the TT.

After another long while, I got to:
info depth 83 seldepth 94 multipv 1 score cp 161 nodes 45427662726490 nps 444674403 hashfull 560 tbhits 2151197975 time 102159383 pv c4a5 g4e2 a5b7 e2b5 b7d8 e8f8 b2b3 f8e8 b6a4 g8h7 a4c5 e8f8 b3b4 b5f1 c5b3 f1c4 b3d4 h7g8 d4f3 c4d5 c7b6 d5b3 f3d2 b3d5 b6a5 d5a8 a5c7 a8b7 d2b3 b7d5 b3c5 d5c6 c5d3 c6e4 d3b2 e4c6 b2d1 c6b5 c7b6 b5a6 d1c3 a6c4 c3a4 g8h7 b6a5 f8e8 a4c5 e8f8 c5e4 c4d3 e4d2 f8g8 d2b3 d3b5 b3c5 g8f8 a5b6 h7g8 c5b3 b5a4 b3d2 a4b5 d2f3 b5f1 b6c7 f1c4 c7a5 c4e2 f3d2 e2b5 d2e4 b5c6 e4c3 c6b7 c3b1 b7a8 a5b6 a8d5 b1d2 f8e8 b6c7 g8h7 d2b1 d5e4 b1c3 e4a8 c3e2 a8b7 e2d4 e8f8 d4b3 b7a6 b3d2 f8e8

Note that in the previous search it did spend a lot of time on Na5 Bf5 and eventually rejected Bf5 for Be2.

I'm letting it run some more to see if anything more enlightening comes up.

[h1a8]

[d]4q1kn/2Bp1p2/1N1PpPp1/1P2P1P1/2N3b1/6p1/1P4Pb/7K w - - 0 1

If the best move is all that is needed, then there seems to be a "lot" of best moves.

I took "best" to mean "key". Have you followed perejaslav's link to the discussion of this study?

I assume many engines will find the initial key sequence, and then get stuck for a long time at 0.00. Like here.

info depth 127 seldepth 41 multipv 1 score cp 0 nodes 1930533338907 nps 63402350 hashfull 1000 tbhits 0 time 30448924 pv c4a5 g4e2 a5b7 e2b5 b7d8 b5e2 b2b4 e2b5 b6c8 b5c6 c8a7 g8h7 c7b6 e8g8 b6a5 c6a8 a5c7 a8d5 b4b5 d5b7 b5b6 b7a6 a7b5 a6b5 b6b7 g8e8 b7b8q b5c4 b8b4 c4d5 b4h4 h7g8 h4h6 e8f8 h6h3 f8e8 h3h4 e8f8 c7b6 f8e8

Here's the winning idea :

[pgn][Event "Computer Chess Test Suite"]
[Site "EPD2diag V1.5"]
[Date "2020.01.27"]
[White "Hard-Talkchess-2020.077"]
[Black "Na5"]
[Result "1-0"]
[FEN "4q1kn/2Bp1p2/1N1PpPp1/1P2P1P1/2N3b1/6p1/1P4Pb/7K w - - 0 1"]
[SetUp "1"]

1. Na5 Be2 2. Nb7 Bd3 3. Nd8 Bxb5 4. b3 Qf8 5. Na4 Kh7 6. Nc3 Bf1 7. b4 Bd3 8. b5 Bxb5 9. Nxb5 Qe8 10. Nd4 Kg8 11. Nf3 Kh7 12. Nxh2 gxh2 13. Kxh2 Kg8 14. Kg3 Kh7 15. Kf3 Kg8 16. Ke4 Kh7 17. Kd4 Kg8 18. Kc5 Kh7 19. Kb6 Kg8 20. Kb7 Kh7 21. Bb6 Kg8 22. Nc6 Kh7 23. Nb8 Kg8 24. Kc7 Kh7 25. Nxd7 1-0[/pgn]

It's not simple to me how white wins afterward.

Is it not clear ?
The d pawn is going to promote.
This is possible because the black is defenseless : the king, the queen and the knight are trapped in a little box.

I played the cpu at least 5 times. Every time there is a wrinkle that makes the game a draw. I go over these games and find there is subtle hidden techniques that need to be done in some lines.
I challenge you to play the cpu (strongest stockfish available) 5 times from the starting position of this puzzle (5 min games). Tell me how you fare.

Is it really important to know how a human would perform in 5 minutes in this study ?
The plan in 4 steps :
1) close the box with Na5-b7-d8
2) wins the white square bishop by pushing the b pawn supported by the knight
3) take the b2 bishop with the knight
4) bring the king to the d7 pawn and take it to queen the d6 pawn

Here's the eval from SF after 1.Na5!
7 best moves after some learning :

Code: Select all

FEN: 4q1kn/2Bp1p2/1N1PpPp1/NP2P1P1/6b1/6p1/1P4Pb/7K b - - 1 1

Stockfish_20080923_x64_modern:
...
 36/41	00:44	 573 418 706	12 802 668	+4,13	1. ... Kf8 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Kg8 5.Na4 Bc6 6.Nc3 Bb7 7.b4 Bd5 8.b5 Bc6 9.Ba5 Ba8 10.Na4 Kh7 11.Bb6 Qg8 12.Bc7 Bd5 13.Nc5 Qe8 14.b6 Bc6 15.b7 Bxb7 16.Ncxb7 Qf8 17.Nc5 Qe8 18.Nb3 Qg8 19.Bb6 Qe8 20.Nd2 Qg8 21.Nf1 Qf8
 37/71	00:44	 573 418 706	12 802 668	+4,51	1. ... Kh7 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Bf1 5.Na4 Qf8 6.Bb6 Bd3 7.Nc3 Ba6 8.Bc7 Bf1 9.Ba5 Kg8 10.Bb6 Ba6 11.Bc7 Bb7 12.b4 Bc6 13.Bb6 Kh7 14.Ba5 Qe8 15.Bc7 Bd5 16.b5 Ba8 17.b6 Bc6 18.Na2 Kg8 19.Nc1 Be4 20.Nb3 Bd5 21.Na5 Ba2 22.b7 Kf8 23.b8R Bd5 24.Nab7 Kg8 25.Bb6 Qf8
 37/59	00:44	 573 418 706	12 802 668	+4,11	1. ... Qf8 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Bf1 5.Na4 Bd3 6.Nc3 Qh6 7.gxh6 g5 8.Bb6 Ng6 9.h7+ Kxh7 10.Nxf7 Kg8 11.Nh6+ Kh7 12.Ng4 Bf5 13.Nxh2 gxh2 14.Bd4 Nf4 15.Kxh2 Bd3 16.Bf2 g4 17.g3 Ne2 18.Nxe2 Bxe2 19.Be3 Kg6 20.Kg2 Ba6 21.b4 Kf7 22.Kg1
 37/68	00:44	 573 418 706	12 802 668	+3,88	1. ... Bf5 2.Nb7 Bd3 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bg5 Bc6 34.Bf6+ Kg8 35.Bd4
 37/67	00:44	 573 418 706	12 802 668	+3,88	1. ... Bd1 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bg5 Bc6 34.Bf6+ Kg8
 37/71	00:44	 573 418 706	12 802 668	+3,88	1. ... Bh5 2.Nb7 Be2 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bc3+ Kg8 34.Bd4 Bb7 35.Kf6 Bc6 36.Be3 Bb7
 37/68	00:44	 573 418 706	12 802 668	+3,88	1. ... Be2 2.Nb7 Bc4 3.Nd8 Bxb5 4.b3 Qf8 5.Na4 Qh6 6.gxh6 g5 7.Nc3 Ng6 8.h7+ Kxh7 9.Nxf7 Kg8 10.Nxg5 Nf4 11.Nf3 Bf1 12.Ne1 Ng6 13.b4 Nxe5 14.Nf3 Nc4 15.Nxh2 gxh2 16.Kxh2 Bd3 17.g4 Kf7 18.g5 Nd2 19.Kg3 e5 20.b5 Ne4+ 21.Nxe4 Bxe4 22.Kg4 Kg6 23.Ba5 Bd5 24.b6 e4 25.Bd2 Bb7 26.Be3 Bd5 27.Kf4 Ba8 28.Ke5 Bb7 29.f7 Kxf7 30.Kf5 Kg7 31.g6 Bc6 32.Bd2 Bd5 33.Bc3+ Kg8 34.Bd4 Bb7

I knew all that before I even played the cpu once. All that can be easily achieved blindfolded. The problem comes after the king gets to d7. In some cases it depends on where blacks king and queen are before you move the knight, otherwise it is a draw. There are other wrinkles as well. That's why I ask you to play stockfish 5 times and you will see for yourself. It's not as easy as you think. I did everything correctly and got king to d7 on my very first attempt. So that's not a problem at all.

Have you seen the analysis presented by the composer?

https://glarean-magazin.ch/2019/01/19/m ... lemschach/

Omg. You need to trust me on this. If I'm wrong then please never listen to anything I say. But please give me the benefit of the doubt. I know this position extremely well now. It is not simple at all. Once Bb6 then moving the knight to c6 depends on the position of the black and queen. For example, if the black king is on h7 then moving the knight to c6 is a draw.
Now assume, the black king is on g8 (queen is always on e8) then Nc6 is winning. But the win still isn't simple. Black has got several trucks to draw.

Now don't get me wrong, after Bb6 the cpu can win this against any entity. The problem is that it is not simple for humans. The study says it is mate in 50 after Nxd7

Don't believe me that it isn’t easy? Play 5 games against stockfish with no take backs. How many did you draw?

[Collingwood]

Guys, I don't want to be the formatting police, but it's really hard to read posts when you quote all of the previous posts. The last post has quotes nested 10 deep.

Please consider using the Post Reply button or editing out stuff if you use the Quote button.