A questionable position

[Hobacle]

[d]6bn/5pPq/5PpB/5pPp/5K2/5B2/8/6k1 w - - 0 1
Can White win here? It's too diffcult for me(and my engines) to get the answer.
If yes, I'll build a great puzzle around it.

[Ras]

Can White win here?

I don't think so, and here's why: White needs to get more material out of the fortress. At some point, that means g7xh8, answered by Qh7xh8. That allows Bh6-f8, but Black's main resource here is h5-h4. That opens h5 as escape square for the queen so that White's light squared bishop must stay on the d1-h5 diagonal. Also, the white King is trapped on h3 to block the pawn, and it cannot capture the pawn, or else the whole h-file opens up for Black's queen. Since g4 is controlled by the black pawn on f5, and h5 by the pawn on g6, White's liqht squared bishop has only d1, e2, and f3. If the black king moves between e1 and f2, the bishop will be kept under attack so that White cannot make progress.

Trying to pseudo-stalemate Black's king so that Black is finally forced to capture on g7 or h6 would be another idea, but I don't see that happening.

On the other hand, any plan involving White's light squared bishop capturing on f7 would be doomed because that would free Black's pieces easily.

[MikeGL]

[d]6bn/5pPq/5PpB/5pPp/5K2/5B2/8/6k1 w - - 0 1
Can White win here? It's too diffcult for me(and my engines) to get the answer.
If yes, I'll build a great puzzle around it.

Looks interesting. Difficult to find a win though.
But a N pair instead of the lone Bf3 seems to mate in less than 60 moves.
[d]6bn/5pPq/5PpB/5pPp/N4K2/8/8/N5k1 w - - 0 1

[peter]

[d]6bn/5pPq/5PpB/5pPp/5K2/5B2/8/6k1 w - - 0 1
Can White win here? It's too diffcult for me(and my engines) to get the answer.

Something tells me, you know quite well, that and how White can, don't you?

Let's take f- and h- Pawn off the board:

[d]6bn/5pPq/5PpB/6P1/5K2/5B2/8/6k1 w - - 0 1

Analysis by Stockfish-MOJO 281120:

1.Ke3 Kf1 2.Bd1 Kg2 3.Be2 Kg3 4.Bf3 Kh4 5.Kf2 Kh3 6.Be2 Kh4 7.Kg2 Qxh6 8.gxh6 Kg5 9.gxh8Q Kf5 10.Qxg8 Ke4 11.h7 Ke3 12.Qd8 g5 13.h8Q g4 14.Qh5 Ke4 15.Qxg4+ Ke3 16.Qf3#
+- (#16) Depth: 79/31 00:00:20 312MN

So all White has to do as long as there are Pawns on board able to move yet still, make them do so by zugzwang, till they can get captured. Way of doing so is to be seen in output- line above from simplified position until Queen has to be sacrificed as only one possible move.

To say it differently: black King has to be "stalemated" (except the Queen- move still possiblbe) at h4 after f- and h- Pawns are removed.

So first moves are the same with original position, instead of 3...Kg3 e.g. ...h4 et seqq.
Pity I can't keep winning eval all the way backward in hash again (easily) to original position, because probably White has to chase the opponent King all around the board two times again before both Pawns are gone, but that, I guess, is your evil intention again, isn't it?

[peter]

Even with only h-Pawn removed from original position, winning line is to be kept in hash at Backward rather easily:

[d]6bn/5pPq/5PpB/5pP1/5K2/5B2/8/6k1 w - - 0 1

Analysis by Stockfish-MOJO 281120:

1.Ke3 Kf1 2.Bd1 Kg1 3.Kf3 Kf1 4.Bc2 Ke1 5.Ke3 Kf1 6.Bd3+ Ke1 7.Be2 f4+ 8.Kf3 Kd2 9.Bf1 Kc1 10.Kxf4 Kd2 11.Ke4 Kc2 12.Kd4 Kb3 13.Ba6 Kb4 14.Bd3 Kb3 15.Bf1 Kb4 16.Ke3 Kc3 17.Bd3 Kb2 18.Ke4 Kc3 19.Bb5 Kb3 20.Be2 Ka2 21.Bc4+ Kb2 22.Kd3 Ka3 23.Kc3 Ka4 24.Bf1 Ka5 25.Bd3 Ka4 26.Kc4 Qxg7 27.Bxg7 Ka5 28.Kc5
+- (50.01) Depth: 53/56 00:00:44 854MN
Yet to be honest, I'm still missing the way to keep Black's King away from h1- promotion-field and yet maintain the zugzwang as for original position with h-Pawn on board.

[peter]

[d]6bn/5pPq/5PpB/5pPp/5K2/5B2/8/6k1 w - - 0 1
Can White win here? It's too diffcult for me(and my engines) to get the answer.
If yes, I'll build a great puzzle around it.

Got it with a final (first) shortcut as for the first 5 moves probably, so DTM will be at least some longer I guess and there are some questions unanswered to me backward to very starting position after other moves then 5...h4(?) and 3...f4+(?)

After

6bn/5pPq/5PpB/5pPp/5K2/5B2/8/6k1 w - - 0 1

1. Ke3 Kf1 2. Be2+ Ke1 3. Bf3 f4+ 4. Kxf4 Kd2 5. Ke4 h4:

6bn/5pPq/5PpB/6P1/4K2p/5B2/3k4/8 w - - 0 1

Analysis by Stockfish-MOJO 281120:

6.Kf4 h3 7.Kg3 Ke3 8.Bh1 h2 9.Kxh2 Kf4 10.Kh3 Ke3 11.Kg4 Kd3 12.Kf4 Kc4 13.Ke4 Kc3 14.Ke5 Kc2 15.Kd4 Kb3 16.Bf3 Kb4 17.Bd5 Kb5 18.Bb3 Kb4 19.Bc4 Ka5 20.Kc5 Ka4 21.Bd5 Ka3 22.Kc4 Kb2 23.Be4 Kc1 24.Kc3 Kd1 25.Bf3+ Ke1 26.Kd3 Kf2 27.Bd5 Ke1 28.Bb3 Qxg7 29.fxg7 Bh7
+- (#53) Depth: 47/55 00:01:24 2000MN

Shortest way to mate after these first 5 moves for me so far:

[pgn][Event "?"]
[Site "?"]
[Date "2021.05.01"]
[Round "?"]
[White "Hobacle, Can"]
[Black "White, Win?"]
[Result "*"]
[SetUp "1"]
[FEN "6bn/5pPq/5PpB/5pPp/5K2/5B2/8/6k1 w - - 0 1"]
[PlyCount "99"]

1. Ke3 Kf1 2. Be2+ Ke1 3. Bf3 f4+ 4. Kxf4 Kd2 5. Ke4 h4 6. Kf4 Ke1 7. Kg4 h3 8.
Kxh3 Kf2 9. Bc6 Ke1 10. Kh2 Kd1 11. Kg3 Ke1 12. Bd5 Ke2 13. Bh1 Kd3 14. Kh3 Kd2
15. Bf3 Kd3 16. Kh2 Kd2 17. Bg2 Kd3 18. Bh1 Kc3 19. Kg3 Kc4 20. Kf3 Kd4 21. Ke2
Kc3 22. Ke3 Kc4 23. Be4 Kc3 24. Bd3 Kb4 25. Kd4 Kb3 26. Be4 Kb4 27. Bc2 Kb5 28.
Bd3+ Kb4 29. Bc4 Ka4 30. Kc3 Ka5 31. Be2 Kb6 32. Kc4 Qxg7 33. Bxg7 Kc6 34. Bxh8
Kd6 35. Kd4 Kc6 36. Bg7 Kb6 37. Bf8 Bh7 38. Kc4 Ka5 39. Bc5 Bg8 40. Bf3 Bh7 41.
Bc6 Ka6 42. Bd5 Bg8 43. Kb4 Bh7 44. Bxf7 Kb7 45. Bd5+ Kc7 46. f7 Kd7 47. f8=Q
Bg8 48. Bd6 Bxd5 49. Qe7+ Kc8 50. Qc7#[/pgn]

Will let it run over night to see, if a full mating- line is to be got in output then regards

[Spliffjiffer]

i came to the same conclusion as you did Peter without reading your posts, just was analysing the last 2 hours or so...isnt it as easy as that? :

1.Ke3 Kf1 2.Bd5 Kg1 (or 2...Ke1 Bg2) 3 Ke2, game over ?

[peter]

i came to the same conclusion as you did Peter without reading your posts, just was analysing the last 2 hours or so...isnt it as easy as that? :

1.Ke3 Kf1 2.Bd5 Kg1 (or 2...Ke1 Bg2) 3 Ke2, game over ?

Yes as for 2...Kg1 (?), but as for your paren- line 2...Ke1 I'm still stuck, could you give some longer line after that?

[Spliffjiffer]

i mean: if 2...Ke1 3.Bg2 and now f4?/h4? its over but if 3...Kd1 the king is cut off...i played 4.Kf2 and i think its just a matter of time to get the black king "stalemated", no?

[peter]

i mean: if 2...Ke1 3.Bg2 and now f4?/h4? its over but if 3...Kd1 the king is cut off...i played 4.Kf2 and i think its just a matter of time to get the black king "stalemated", no?

Yes with 3...f4 (?) or ...h4(?), but it's still a matter of how much time (DTM) and as long as I don't have such a forced mating line I'm not fully sure, if Black can't escape yet still. As for a study, that isn't a mate in x- problem, DTM doesn't really matter, for the engines it does.
That's the problem with positions, if you can't "convince" the engines of your human eval, at least to me then there's always some work to be done still.

Till tomorrow (today) regards