Hard Puzzle for June

[Hobacle]

Well, but I don't think FF2 can beat SF11 in this position.

[d]4k3/7K/8/8/p4ppp/4pprb/1NBprpn1/4bqnR w - - 0 1

Can White win here?
Yes it looks messy, but we can't judge positions by their appearance

[peter]

Well, but I don't think FF2 can beat SF11 in this position.

[d]4k3/7K/8/8/p4ppp/4pprb/1NBprpn1/4bqnR w - - 0 1

Can White win here?

YADKWBO (yet another driving King with Bishop only) variation?

Start is 1.Bxa4+... 2.Nd1, then the ways of guiding black King with white Bishop, King and Zugzwang known from the other puzzles like this. Guidance has to be to h5 or a8, then taking two steps with Knight, to e4, if it's h5 or to b5, if it's a8, Black's King is at then, thus cutting the only escape- fields uncovered by white King. Between these two final Knight-moves promotion of black d-Pawn doesn't matter anymore and Bishop can mate on one of these two white fields, a8 or h5. Right?

Finding not much time at the moment, the rest I will leave to Spliffjiffer regards

[peter]

Guidance has to be to h5 or a8, then taking two steps with Knight, to e4, if it's h5 or to b5, if it's a8, Black's King is at then, thus cutting the only escape- fields uncovered by white King. Between these two final Knight-moves promotion of black d-Pawn doesn't matter anymore and Bishop can mate on one of these two white fields, a8 or h5. Right?

On the other hand, having tried some more in the meantime, I don't see how Black's King can be prevented from escaping always to one of the black coloured edges a1 or h8, where no mate seems to be possible to me at white coloured squares nearby.
Haven't found any forced mate till now, neither has Chest within 100 moves, which seems much too much DTM here, so I'd yet rather say, this ones doesn't really work regards

[peter]

Haven't found any forced mate till now, neither has Chest within 100 moves, which seems much too much DTM here

Oops, wrong starting position with Chest after 2.Nd1?

After restart from original position, Chest right now said #52:

4k3/7K/8/8/p4ppp/4pprb/1NBprpn1/4bqnR w - -

Engine: ChestUCI Ver.5.2 (0 MB)
von Franz Huber

52.00 66:39 +M52 1.Lxa4+ Kf8 2.Ld1 Kf7 3.Sa4 Kf6
4.Sc5 Kf7 5.Sb3 Kf6 6.Kh6 Kf7 7.Kg5 Ke6
8.Kg6 Ke5 9.Kf7 Kd6 10.Kf6 Kd5
11.Kf5 Kd6 12.Ke4 Kc6 13.Kd4 Kb5
14.Kd5

Pasting output- lines once and again till mate is reached:

[pgn][Event "?"]
[Site "?"]
[Date "2021.06.29"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[SetUp "1"]
[FEN "4k3/7K/8/8/p4ppp/4pprb/1NBprpn1/4bqnR w - -"]

1. Bxa4+ Kf8 2. Bd1 Kf7 3. Na4 Kf6 4. Nc5 Kf7 5. Nb3 Kf6
6. Kh6 Kf7 7. Kg5 Ke6 8. Kg6 Ke5 9. Kf7 Kd6 10. Kf6 Kd5
11. Kf5 Kd6 12. Ke4 Kc6 13. Kd4 Kb5 14. Kd5 Kb4 15. Na1 Kb5
16. Nc2 Kb6 17. Nd4 Kb7 18. Kc5 Ka6 19. Nc6 Kb7 20. Nd8+
Kb8 21. Ne6 Ka7 22. Kb5 Kb7 23. Rh2 Ka7 24. Nc5 Kb8 25. Kb6
Kc8 26. Rh1 Kb8 27. Nd7+ Kc8 28. Kc6 Kd8 29. Nb6 Ke7
30. Kd5 Ke8 31. Kd6 Kd8 32. Rh2 Ke8 33. Nc8 Kf8 34. Ne7 Ke8
35. Nc6 Kf7 36. Nd4 Kf8 37. Ke6 Ke8 38. Nc6 Kf8 39. Na5 Ke8
40. Nb7 Kf8 41. Nd6 Kg7 42. Ke7 Kg6 43. Rh1 Kg7 44. Nf5+
Kg8 45. Rh2 Kh8 46. Kf7 Kh7 47. Nd6 Kh8 48. Rh1 Kh7
49. Bc2+ Kh6 50. Kf6 d1=Q 51. Nf7+ Kh5 52. Bg6# *[/pgn]

Simply was too fixed on the YADKWBO (yet another driving King with Bishop only), should have tried the Driving King with Knight only instead, woe is me!
Congrats, Hobacle, you fooled me again regards

[Ignacio]

FEN: 4k3/7K/8/8/p4ppp/4pprb/1NBprpn1/4bqnR w - - 0 1

Chest 5.2:
FEN: 4k3/7K/8/8/p4ppp/4pprb/1NBprpn1/4bqnR w - - (4+16)
Position-Analysis: C0/R0/K6/P3/X10 W:4/20
Search for 1. Special-Mate [C6/R0/K0/P2/X8] in 52 ... (Hash=2044MB)
52 01:27 112.638.348 1.307.240 +M52 Ac2xa4+
Search completed ... (Time=87.47s)
Mate in 52 found ! (1. Solution in 01:27)
52/52 01:27 114.350.384 1.307.235 +M52 Ac2xa4+ Re8-f8 Aa4-d1 Rf8-f7 Cb2-a4 Rf7-f6 Ca4-c5 Rf6-f7 Cc5-b3 Rf7-f6 Rh7-h6 Rf6-f7 Rh6-g5 Rf7-e6 Rg5-g6 Re6-e5 Rg6-f7 Re5-d6 Rf7-f6 Rd6-d5 Rf6-f5 Rd5-d6 Rf5-e4 Rd6-c6 Re4-d4 Rc6-b5 Rd4-d5 Rb5-b4 Cb3-a1 Rb4-b5 Ca1-c2 Rb5-b6 Cc2-d4 Rb6-b7 Rd5-c5 Rb7-a6 Cd4-c6 Ra6-b7 Cc6-d8+ Rb7-b8 Cd8-e6 Rb8-a7 Rc5-b5 Ra7-b7 Th1-h2 Rb7-a7 Ce6-c5 Ra7-b8 Rb5-b6 Rb8-c8 Th2-h1 Rc8-b8 Cc5-d7+ Rb8-c8 Rb6-c6 Rc8-d8 Cd7-b6 Rd8-e7 Rc6-d5 Re7-e8 Rd5-d6 Re8-d8 Th1-h2 Rd8-e8 Cb6-c8 Re8-f8 Cc8-e7 Rf8-e8 Ce7-c6 Re8-f7 Cc6-d4 Rf7-f8 Rd6-e6 Rf8-e8 Cd4-c6 Re8-f8 Cc6-a5 Rf8-e8 Ca5-b7 Re8-f8 Cb7-d6 Rf8-g7 Re6-e7 Rg7-g6 Th2-h1 Rg6-g7 Cd6-f5+ Rg7-g8 Th1-h2 Rg8-h8 Re7-f7 Rh8-h7 Cf5-d6 Rh7-h8 Th2-h1 Rh8-h7 Ad1-c2+ Rh7-h6 Rf7-f6 d2-d1D Cd6-f7+ Rh6-h5 Ac2-g6+

[peter]

FEN: 4k3/7K/8/8/p4ppp/4pprb/1NBprpn1/4bqnR w - - 0 1

Chest 5.2:
FEN: 4k3/7K/8/8/p4ppp/4pprb/1NBprpn1/4bqnR w - - (4+16)
Position-Analysis: C0/R0/K6/P3/X10 W:4/20
Search for 1. Special-Mate [C6/R0/K0/P2/X8] in 52 ... (Hash=2044MB)
52 01:27 112.638.348 1.307.240 +M52 Ac2xa4+
Search completed ... (Time=87.47s)
Mate in 52 found ! (1. Solution in 01:27)
52/52 01:27 114.350.384 1.307.235 +M52 Ac2xa4+ Re8-f8 Aa4-d1 Rf8-f7 Cb2-a4 Rf7-f6 Ca4-c5 Rf6-f7 Cc5-b3 Rf7-f6 Rh7-h6 Rf6-f7 Rh6-g5 Rf7-e6 Rg5-g6 Re6-e5 Rg6-f7 Re5-d6 Rf7-f6 Rd6-d5 Rf6-f5 Rd5-d6 Rf5-e4 Rd6-c6 Re4-d4 Rc6-b5 Rd4-d5 Rb5-b4 Cb3-a1 Rb4-b5 Ca1-c2 Rb5-b6 Cc2-d4 Rb6-b7 Rd5-c5 Rb7-a6 Cd4-c6 Ra6-b7 Cc6-d8+ Rb7-b8 Cd8-e6 Rb8-a7 Rc5-b5 Ra7-b7 Th1-h2 Rb7-a7 Ce6-c5 Ra7-b8 Rb5-b6 Rb8-c8 Th2-h1 Rc8-b8 Cc5-d7+ Rb8-c8 Rb6-c6 Rc8-d8 Cd7-b6 Rd8-e7 Rc6-d5 Re7-e8 Rd5-d6 Re8-d8 Th1-h2 Rd8-e8 Cb6-c8 Re8-f8 Cc8-e7 Rf8-e8 Ce7-c6 Re8-f7 Cc6-d4 Rf7-f8 Rd6-e6 Rf8-e8 Cd4-c6 Re8-f8 Cc6-a5 Rf8-e8 Ca5-b7 Re8-f8 Cb7-d6 Rf8-g7 Re6-e7 Rg7-g6 Th2-h1 Rg6-g7 Cd6-f5+ Rg7-g8 Th1-h2 Rg8-h8 Re7-f7 Rh8-h7 Cf5-d6 Rh7-h8 Th2-h1 Rh8-h7 Ad1-c2+ Rh7-h6 Rf7-f6 d2-d1D Cd6-f7+ Rh6-h5 Ac2-g6+

Good parameters of yours. I had P2 only, rest 0, with your setting 2'36" at my hardware too.
Of course, knowing the DTM already, helps also regards

[Hobacle]

Haven't found any forced mate till now, neither has Chest within 100 moves, which seems much too much DTM here

Oops, wrong starting position with Chest after 2.Nd1?

After restart from original position, Chest right now said #52:

4k3/7K/8/8/p4ppp/4pprb/1NBprpn1/4bqnR w - -

Engine: ChestUCI Ver.5.2 (0 MB)
von Franz Huber

52.00 66:39 +M52 1.Lxa4+ Kf8 2.Ld1 Kf7 3.Sa4 Kf6
4.Sc5 Kf7 5.Sb3 Kf6 6.Kh6 Kf7 7.Kg5 Ke6
8.Kg6 Ke5 9.Kf7 Kd6 10.Kf6 Kd5
11.Kf5 Kd6 12.Ke4 Kc6 13.Kd4 Kb5
14.Kd5

Pasting output- lines once and again till mate is reached:

[pgn][Event "?"]
[Site "?"]
[Date "2021.06.29"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[SetUp "1"]
[FEN "4k3/7K/8/8/p4ppp/4pprb/1NBprpn1/4bqnR w - -"]

1. Bxa4+ Kf8 2. Bd1 Kf7 3. Na4 Kf6 4. Nc5 Kf7 5. Nb3 Kf6
6. Kh6 Kf7 7. Kg5 Ke6 8. Kg6 Ke5 9. Kf7 Kd6 10. Kf6 Kd5
11. Kf5 Kd6 12. Ke4 Kc6 13. Kd4 Kb5 14. Kd5 Kb4 15. Na1 Kb5
16. Nc2 Kb6 17. Nd4 Kb7 18. Kc5 Ka6 19. Nc6 Kb7 20. Nd8+
Kb8 21. Ne6 Ka7 22. Kb5 Kb7 23. Rh2 Ka7 24. Nc5 Kb8 25. Kb6
Kc8 26. Rh1 Kb8 27. Nd7+ Kc8 28. Kc6 Kd8 29. Nb6 Ke7
30. Kd5 Ke8 31. Kd6 Kd8 32. Rh2 Ke8 33. Nc8 Kf8 34. Ne7 Ke8
35. Nc6 Kf7 36. Nd4 Kf8 37. Ke6 Ke8 38. Nc6 Kf8 39. Na5 Ke8
40. Nb7 Kf8 41. Nd6 Kg7 42. Ke7 Kg6 43. Rh1 Kg7 44. Nf5+
Kg8 45. Rh2 Kh8 46. Kf7 Kh7 47. Nd6 Kh8 48. Rh1 Kh7
49. Bc2+ Kh6 50. Kf6 d1=Q 51. Nf7+ Kh5 52. Bg6# *[/pgn]

Simply was too fixed on the YADKWBO (yet another driving King with Bishop only), should have tried the Driving King with Knight only instead, woe is me!
Congrats, Hobacle, you fooled me again regards

Can you be sure #52 is the shortest?

[Hobacle]

Can you be sure #52 is the shortest?

I've just found that there's only one solution of #52 so it's almost certainly the shortest.
Have to admit it's a bit out of my expectation. So if White King is at h8 instead of at h7 in the original position, what about it then?

[peter]

Can you be sure #52 is the shortest?

I've just found that there's only one solution of #52 so it's almost certainly the shortest.
Have to admit it's a bit out of my expectation. So if White King is at h8 instead of at h7 in the original position, what about it then?

[d]4k2K/8/8/8/p4ppp/4pprb/1NBprpn1/4bqnR w - -
Stellungs-Analyse: C0/R0/K6/P3/X10 W:4/19
Suche nach Spezial-Matt [C6/R0/K0/P2/X8] in 55 ... (Hash=2044MB)
53.02 2:37 +M53 1.Lxa4+ 744
Suche abgeschlossen ... (Zeit=159.65s)
Matt in 53 gefunden ! (1 Lösung in 02:39)
53/53 2:39 +M53 1.Lxa4+ Kf8 2.Ld1 Kf7 3.Sa4 Kf8 4.Sc5 Kf7 5.Kh7 Kf6 6.Kh6 Kf5 7.Kg7 Ke5 8.Sb3 Ke6 9.Kg6 Ke5 10.Kf7 Kd6 11.Kf6 Kd5 12.Kf5 Kd6 13.Ke4 Kc6 14.Kd4 745
[pgn]
[Event "?"]
[Site "?"]
[Date "2021.06.30"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[SetUp "1"]
[FEN "4k2K/8/8/8/p4ppp/4pprb/1NBprpn1/4bqnR w - -"]

1. Bxa4+ Kf8 2. Bd1 Kf7 3. Na4 Kf8 4. Nc5 Kf7 5. Kh7 Kf6
6. Kh6 Kf5 7. Kg7 Ke5 8. Nb3 Ke6 9. Kg6 Ke5 10. Kf7 Kd6
11. Kf6 Kd5 12. Kf5 Kd6 13. Ke4 Kc6 14. Kd4 Kb5 15. Kd5 Kb4
16. Na1 Kb5 17. Nc2 Kb6 18. Nd4 Kb7 19. Kc5 Ka6 20. Nc6 Kb7
21. Nd8+ Kb8 22. Ne6 Ka7 23. Kb5 Kb7 24. Rh2 Ka7 25. Nc5
Kb8 26. Kb6 Kc8 27. Rh1 Kb8 28. Nd7+ Kc8 29. Kc6 Kd8
30. Nb6 Ke7 31. Kd5 Ke8 32. Kd6 Kd8 33. Rh2 Ke8 34. Nc8 Kf8
35. Ne7 Ke8 36. Nc6 Kf7 37. Nd4 Kf8 38. Ke6 Ke8 39. Nc6 Kf8
40. Na5 Ke8 41. Nb7 Kf8 42. Nd6 Kg7 43. Ke7 Kg6 44. Rh1 Kg7
45. Nf5+ Kg8 46. Rh2 Kh8 47. Kf7 Kh7 48. Nd6 Kh8 49. Rh1
Kh7 50. Bc2+ Kh6 51. Kf6 d1=Q 52. Nf7+ Kh5 53. Bg6# *
[/pgn]

[Jim Logan]

Try as I might, and I'll be the first to admit I'm not very good at searching - I cannot find Chest 5.2. Chest 3.19 is one thing, but it seems like some work to go to 5.2. Can anyone help? Even via PM?