Hard Puzzle for June

[Ajedrecista]

Hello Jim:

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?

Try here:

https://fhub.jimdofree.com/

ChestUCI_V52.zip (520.6 KB)

------------

Regarding the original post, he managed to compose a great puzzle... again. Congratulations! Not to be ashamed at all because it is only a checkmate in less than 60 moves!

Regards from Spain.

Ajedrecista.

[Jim Logan]

Thanks, Ajedrecista. You are very kind.

Jim

[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?

[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]

Well, this is what I want, and now you should pay some attention to the 50-move rule!

[peter]

Well, this is what I want, and now you should pay some attention to the 50-move rule!

Already at the first position with White's King at h7, engines show at Backward not quite the shortest DTM, prefering 50...Kh5 to ...d1Q (both #2), because 50...Kh5 51.Bg6+ was remis according to 50 moves boundary, and 51.Rxg1 makes DTM longer. Thus DTM at backward is 53 instead of 52:

[d]8/8/3N1K2/7k/5ppp/4pprb/2Bprpn1/4bqnR w - - 0 1

51.Rxg1 fxg1D 52.Bg6+ Kh6 53.Nf5#

With starting position white King at h8, already 50.Bc2+ was remis, yet there's still the detour

[d]8/5K1k/3N4/8/5ppp/4pprb/3prpn1/3BbqnR w - - 0 1

50.Rxg1 Kh6 51.Rxf1 Kg5 52.Kg7 Kh5 53.Bc2 Kg5 54.Sf7+ Kh5 55.Lg6#

That helps the engines in Backward to keep mating score in output, even if with 2 moves too much DTM.
Guess it's just a matter of taste, what you prefer, isn't it regards

[Hobacle]

Already at the first position with White's King at h7, engines show at Backward not quite the shortest DTM, prefering 50...Kh5 to ...d1Q (both #2), because 50...Kh5 51.Bg6+ was remis according to 50 moves boundary, and 51.Rxg1 makes DTM longer. Thus DTM at backward is 53 instead of 52:

[d]8/8/3N1K2/7k/5ppp/4pprb/2Bprpn1/4bqnR w - - 0 1

51.Rxg1 fxg1D 52.Bg6+ Kh6 53.Nf5#

No, 53 moves is not enough. 44...Kg6!

[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?

[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]

45...Kg6! then how can White win under the 50-move rule?
And, why doesn't Chest consider the 50-move rule...

[peter]

45...Kg6! then how can White win under the 50-move rule?
And, why doesn't Chest consider the 50-move rule...

1.) White cannot.
2.) Because Chest is a mate solving program, not a game playing one.
Did you plan to build a puzzle according to the normal game playing rules?
Then you failed with the second version, as it seems, you won't get <50 moves according to Chest till Pawn- move or reduction of material happens. First version did work, second one not anymore.
Maybe Chest is wrong, but then at least I for myself am not able to find a shorter correct line. Do you? You'd have to take with the Rook anywhere sooner then at the very end to reset 50 moves, but will that work for winning at all?

BTW as for normal game playing, it that matters too, I then would try positions somewhat nearer to practical game playing. It won't be easy to get the Rook to a1 with all black pieces surrounding it like here, it's a legal position but it won't be reached in normal game playing, will it?

Yes it looks messy, but we can't judge positions by their appearance

It's a great puzzle to me, but somewhat told me from the very start, you wouldn't be confident so easily on your own once again.

[Hobacle]

45...Kg6! then how can White win under the 50-move rule?
And, why doesn't Chest consider the 50-move rule...

1.) White cannot.
2.) Because Chest is a mate solving program, not a game playing one.
Did you plan to build a puzzle according to the normal game playing rules?
Then you failed with the second version, as it seems, you won't get <50 moves according to Chest till Pawn- move or reduction of material happens. First version did work, second one not anymore.
Maybe Chest is wrong, but then at least I for myself am not able to find a shorter correct line. Do you? You'd have to take with the Rook anywhere sooner then at the very end to reset 50 moves, but will that work for winning at all?

BTW as for normal game playing, it that matters too, I then would try positions somewhat nearer to practical game playing. It won't be easy to get the Rook to a1 with all black pieces surrounding it like here, it's a legal position but it won't be reached in normal game playing, will it?

Yes it looks messy, but we can't judge positions by their appearance

It's a great puzzle to me, but somewhat told me from the very start, you wouldn't be confident so easily on your own once again.

In my opinion, a composition with a draw by the 50-move rule or a win just under the 50-move rule can be called the crown jewel in chess composing. I found one here:
viewtopic.php?f=2&t=59727&start=10#p666653
Then I decided to compose my own one. It seems I succeeded.

No I was not so confident this time indeed but I've never been very confident in fact.
You know, there're three Black Bishops in the puzzle on April 1st.
The rambing rook one doesn't have any wonderful moves.
Hard Puzzle for May, my best one in my opinion, starts too directly.
This one also starts directly, but Hard Puzzle for May has 1.Ka6!! and 4.Kb4!!, this one doesn't have. The difficulty besides the limit of the 50-move rule is only the choice between Nd1 and Bd1, this is not enough. And it looks messy indeed. Or, who wouldn't doubt the role of the White Rook?
A profect composition in my thought has a bright but unnoticeable theme and several wonderful moves.
I posted this composition in March:
[pgn][Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[SetUp "1"]
[FEN "rqbnr2k/2p2pp1/2p4p/p1QP4/6N1/PP3R1B/2P4P/1K2bR2 w - - 0 1"]
[PlyCount "9"]

1. Nf6 $3 gxf6 2. Qd4 Qb6 3. Qf4 $1 cxd5 4. Qxh6+ Kg8 5. Be6 $3 *

[/pgn]
But it was my first time to post composition here. And it's not hard for engines to solve.

So... I've never been satisfied with myself.