once labeled one of the most difficult of the world...

[Vinvin]

I tries to prove the mate on my PC, it's quite hard :

After a bit of learning after 1.f4, 5 best moves (3 moves proved, still 1... Bxf4 and 1... Bf6) :

Code: Select all

FEN: 4K1k1/8/1p5p/1Pp3b1/5P2/1P6/P1B2P2/8 b - - 0 1

Stockfish_170713_matefinder:
 37/29	06:01	 5 638 072k	15 604k	+M13	1. ... c4 2.fxg5 hxg5 3.bxc4 Kg7 4.c5 g4 5.cxb6 g3 6.fxg3 Kf6 7.b7 Ke6 8.b8Q Kd5 9.b6 Kc4 10.Qc7+ Kd4 11.b7 Ke3 12.Qf4+ Ke2 13.b8Q Ke1 14.Qbe5+
 38/33	06:01	 5 638 072k	15 604k	+M16	1. ... Kg7 2.fxg5 hxg5 3.a4 Kf6 4.a5 bxa5 5.b6 Ke5 6.b7 Kd4 7.b8Q Kc3 8.Bd1 g4 9.Qb5 Kd2 10.Bxg4 Kc2 11.Qxc5+ Kb2 12.Bd1 a4 13.bxa4 Kb1 14.Qc2+ Ka1 15.Qe2 Kb1 16.Bb3 Kc1 17.Qc2+
 38/71	06:01	 5 638 072k	15 604k	+M35	1. ... Bh4 2.a4 Bxf2 3.a5 bxa5 4.b6 Bg3 5.f5 Kg7 6.Ke7 Bh4+ 7.Ke6 Bg3 8.f6+ Kf8 9.Bg6 Be1 10.b7 Bg3 11.Kd7 Be5 12.Kc8 h5 13.Bxh5 c4 14.bxc4 a4 15.Bd1 a3 16.Bb3 Kf7 17.c5+ Kxf6 18.b8Q Bxb8 19.Kxb8 Ke5 20.c6 Kd4 21.c7 Kc3 22.Be6 Kd3 23.c8Q Kd4 24.Bb3 Ke4 25.Qg4+ Ke3 26.Qg3+ Ke4 27.Bc2+ Kd5 28.Qxa3 Ke5 29.Qg3+ Kf6 30.Qf3+ Kg5
 38/70	06:01	 5 638 072k	15 604k	+51,91	1. ... Bxf4 2.Kd7 Bg5 3.Kc7 Kf7 4.a4 Ke6 5.Kxb6 Kd6 6.a5 Bd8+ 7.Ka6 c4 8.b6 cxb3 9.Bxb3 Kc5 10.b7 Bc7 11.Ka7 h5 12.a6 Kb5 13.Bd1 Be5 14.Be2+ Kc6 15.b8Q Kd5 16.Bxh5 Bd4+ 17.Ka8 Bf6 18.Qf4 Ke6 19.Bg4+ Ke7 20.Qxf6+ Kxf6 21.Kb7 Ke7
 38/70	06:01	 5 638 072k	15 604k	+28,91	1. ... Bf6 2.a4 Bc3 3.f5 Kg7 4.Ke7 c4 5.bxc4 Bb4+ 6.Kd7 h5 7.Kc6 h4 8.Kxb6 Kf6 9.a5 Ke5 10.a6 Kd4 11.Kc6 Bc5 12.b6 h3 13.a7 h2 14.Be4 Bf8 15.a8Q Kxe4 16.Kb5+ Kd3 17.c5 Ke2 18.Qg2 Bg7 19.Qxh2 Bc3 20.c6 Bd4 21.f4+ Kf3 22.c7 Kg4 23.c8Q Ba1 24.b7 Bd4 25.b8Q

After one night of thinking :

5 best moves after 1.f4 Bxf4 2.Kd7 :

Code: Select all

FEN: 6k1/3K4/1p5p/1Pp5/5b2/1P6/P1B2P2/8 b - - 1 2

Stockfish_170713_matefinder:

 51/75	6:41:52	693 595 514k	28 765k	+M34	2. ... Bd2 3.Kc6 Ba5 4.b4 cxb4 5.Bb3+ Kg7 6.Kd5 Kf6 7.Ke4 h5 8.Kf4 Kg6 9.Ke5 h4 10.Kf4 h3 11.Kg3 Kg5 12.f3 h2 13.Kxh2 Kh4 14.Kg2 Kh5 15.Kg3 Kg5 16.f4+ Kf5 17.Kf3 Kf6 18.Kg4 Kg6 19.f5+ Kf6 20.Kf4 Ke7 21.Kg5 Kd6 22.f6 Kd7 23.f7 Ke7 24.Kh5 Kf8 25.Kh6 Ke7 26.Kg7 Kd6 27.f8Q+ Ke5 28.Qf3 Kd4 29.Qf4+ Kd3 30.Kg6 Ke2 31.Kg5
-
 51/68	6:41:52	693 595 514k	28 765k	+M35	2. ... h5 3.Kc6 h4 4.a4 h3 5.Kxb6 Bg5 6.Kc6 Kg7 7.a5 Kf6 8.a6 Ke5 9.a7 h2 10.Be4 Kxe4 11.a8Q Kf3 12.Kxc5+ Kxf2 13.b6 Be3+ 14.Kb5 Bf4 15.Qe4 Bb8 16.b7 Bg3 17.Qc2+ Kf1 18.Qd3+ Kg2 19.Qxg3+ Kxg3 20.b8Q+ Kg2 21.Qa8+ Kg1 22.b4 h1R 23.Qxh1+ Kxh1 24.Kc6 Kg1 25.b5 Kf1 26.b6 Kg2 27.b7 Kg3 28.b8Q+ Kg4 29.Kd5 Kf3 30.Qf8+ Kg3 31.Qf5 Kg2 32.Qg5+ Kf3 33.Kd4 Kf2
-
 51/79	6:41:52	693 595 514k	28 765k	+M35	2. ... Kg7 3.Kc6 Bg5 4.Kxb6 h5 5.Kc6 h4 6.a4 Kf6 7.a5 h3 8.a6 Ke5 9.a7 h2 10.Be4 Kxe4 11.a8Q Kf3 12.Kxc5+ Kxf2 13.b6 Be3+ 14.Kb5 Bf4 15.Qe4 Bb8 16.b7 Bg3 17.Qc2+ Kf1 18.Qd3+ Kg2 19.Qxg3+ Kxg3 20.b8Q+ Kg2 21.Qa8+ Kg1 22.b4 h1R 23.Qxh1+ Kxh1 24.Kc6 Kg2 25.b5 Kf2 26.b6 Ke2 27.b7 Kd2 28.Kd5 Ke3 29.b8Q Kf3 30.Qh2 Kg4 31.Qe5 Kh4 32.Qg7 Kh5
-
 51/69	6:41:52	693 595 514k	28 765k	+M36	2. ... Bg5 3.Kc7 h5 4.Kxb6 h4 5.a4 h3 6.Kc6 Kg7 7.a5 Kf6 8.a6 Ke5 9.a7 h2 10.Be4 Kxe4 11.a8Q Kf3 12.Kxc5+ Kxf2 13.b6 Be3+ 14.Kb5 Bf4 15.Qe4 Bb8 16.b7 Bg3 17.Qc2+ Kf1 18.Qd3+ Kg2 19.Qxg3+ Kxg3 20.b8Q+ Kg2 21.Qa8+ Kg1 22.b4 h1R 23.Qxh1+ Kxh1 24.Kc6 Kh2 25.b5 Kg2 26.b6 Kg3 27.b7 Kf2 28.b8Q Ke3 29.Qg3+ Ke4 30.Qg4+ Ke3 31.Kd5
-
 52/79	6:41:52	693 595 514k	28 765k	+M39	2. ... Be5 3.Kc6 c4 4.Kxb6 c3 5.a4 Bd4+ 6.Kb7 h5 7.a5 h4 8.a6 h3 9.a7 Bxa7 10.Kxa7 h2 11.b6 h1Q 12.b7 Kg7 13.b8Q Qc1 14.Qe5+ Kf8 15.Qh8+ Kf7 16.Qxc3 Qa3+ 17.Kb7 Kg8 18.Qg3+ Kf7 19.Qf4+ Kg7 20.Qg4+ Kf7 21.b4 Qb2 22.Qf3+ Kg7 23.Qf4 Qa1 24.Qg5+ Kf7 25.Bb3+ Kf8 26.Qg8+ Ke7 27.Qf7+ Kd8 28.Bc2 Qe5 29.Qf8+ Qe8 30.Qxe8+ Kxe8 31.Kc6 Ke7 32.b5 Ke6 33.b6 Ke5 34.b7 Kd4 35.b8Q Kc3

[lech]

[d]4K1k1/8/1p5p/1Pp3b1/8/1P3P2/P1B2P2/8 w - - bm f4;
dual core, 1024 M Hash, 13 minutes

Code: Select all

info depth 34 multipv 1 score cp 153 nodes 562710041 nps 969302 time 580531 pv c2f5 h6h5 e8d7 g5d2 f3f4 g8f8 d7c6 d2a5 a2a3 h5h4 f5c8 f8g7 c6c7 g7f6 c8g4 f6f7 g4f5 f7e7 f5h3 e7f6 h3g4
info depth 35
info currmove c2f5 currmovenumber 1
info currmove e8d7 currmovenumber 2
info currmove a2a4 currmovenumber 3
info currmove f3f4 currmovenumber 4
info depth 35 multipv 1 score cp 161 lowerbound nodes 806430774 nps 975349 time
826812 pv f3f4
info currmove f3f4 currmovenumber 1
info depth 35 multipv 1 score cp 169 lowerbound nodes 812343773 nps 974655 time
833468 pv f3f4
info currmove f3f4 currmovenumber 1
info depth 35 multipv 1 score cp 181 lowerbound nodes 828402422 nps 971662 time
852562 pv f3f4
info currmove f3f4 currmovenumber 1
info depth 35 multipv 1 score cp 200 lowerbound nodes 843463037 nps 969219 time
870250 pv f3f4
info currmove f3f4 currmovenumber 1
info depth 35 multipv 1 score cp 227 lowerbound nodes 920209777 nps 958052 time
960500 pv f3f4
info currmove f3f4 currmovenumber 1
info depth 35 multipv 1 score cp 268 lowerbound nodes 971228576 nps 952681 time
1019468 pv f3f4
info currmove f3f4 currmovenumber 1
info depth 35 multipv 1 score cp 329 lowerbound nodes 1065920638 nps 946078 time
 1126672 pv f3f4
info currmove f3f4 currmovenumber 1
info currmove c2f5 currmovenumber 2
info currmove c2e4 currmovenumber 3
info currmove a2a4 currmovenumber 4
info currmove c2d1 currmovenumber 5
info currmove b3b4 currmovenumber 6
info currmove e8d7 currmovenumber 7
info currmove c2g6 currmovenumber 8
info currmove c2d3 currmovenumber 9
info currmove a2a3 currmovenumber 10
info currmove c2h7 currmovenumber 11
info currmove c2b1 currmovenumber 12
info depth 35 multipv 1 score cp 335 nodes 1203219818 nps 940394 time 1279484 pv f3f4 g5f6 a2a4 f6c3 f4f5 g8g7 e8e7 c3f6 e7e6 f6c3 c2d1 c3d2 f5f6 g7f8 f2f4 d2b4 d1h5 b4c3 h5f7 c3a5 f4f5 a5c3 f7g6 c3d2 f6f7 d2b4 f5f6 b4c3 e6d5

In my opinion, it is not a difficult position.
I am very happy that my pioneering project Sting is followed by many other ones like McBrain.
Sting is based on Stockfish 2.1.1 and is worse: "40/4 CEGT" ~30 ELO, "40/40 CCRL" ~15 ELO only.

[Vinvin]

I tries to prove the mate on my PC, it's quite hard

That's true, Vincent.

Still don't make it to let MateFinder keep the mating- output with correct number of moves in hash back to start postion.

and 3 best moves after 1.f4 Bf6 2.a4 :

About that I'm rather sure, after 1...Bf6 2.Kd7 is shorter than a4.
Here's my latest whole hog:

[pgn]
[Event "1st Prize, Sachova skladba "]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "Salai, Ladislav jr."]
[Black "10MV Eret90, Major Dual 1.Bd1"]
[Result "1-0"]
[Annotator "Martan,Peter"]
[SetUp "1"]
[FEN "4K1k1/8/1p5p/1Pp3b1/8/1P3P2/P1B2P2/8 w - - 0 1"]
[PlyCount "59"]
[EventDate "2013.??.??"]

1. f4 $1 (1. Kd7 $2 Bd2 2. Kc6 (2. f4 h5 3. Kc6 Ba5 4. Bd1 h4 5. b4 Bxb4 6.
Kxb6 c4 7. a4 h3) 2... Ba5 3. b4 $1 cxb4 4. Bb3+ Kg7 5. Kd5 Kf6 6. Ke4 h5 $1 7.
Kf4 Kg6 8. Ke5 h4 9. Kf4 Kh5) (1. Bd1 Kg7 (1... Bh4 $5 2. Kd7 Bxf2 3. Kc6 h5 4.
Kxb6 c4+ 5. Ka5 c3 6. Kb4 Be1 7. Kc4 h4 8. f4 Kf7 9. Kd3 Ke6 10. Bg4+ Kd5 11.
f5 c2 12. Kxc2 Ke5 13. a4 Kf6 14. b6 h3 15. Bxh3 Bg3 16. b7 Kg5 17. Kc3 Kh4 18.
Kc4 Be5 19. a5 Kg5 20. b4 Bb8 21. a6 Kf4 22. f6 Kg3 23. f7 Kxh3 24. f8=Q Ba7
25. b8=Q Bxb8 26. Qxb8 Kg4 27. a7 Kg5 28. Qg3+ Kf5 29. a8=Q Kf6 30. Qf8+ Ke6
31. Qgd6#) (1... Bd2 $5 2. f4 (2. Kd7 $2 {ZUS 1.Kd7}) 2... Bxf4 3. Kd7 Bd2 4.
Kc6 Ba5 5. b4 cxb4 6. Bb3+ {ZUS 1.f4 + 1 Zug}) (1... Bf4 $5 2. Kd7 Kf7 3. Kc6
Ke6 4. Kxb6) 2. Kd7 Bd2 3. f4 Kg6 4. Bg4 h5 5. f5+ Kf6 6. Bxh5 Kxf5 7. Kc6 Ba5
8. a3 Ke5 9. Bg4 Kf4 10. f3 Ke5 11. b4 cxb4 12. axb4 Bxb4 13. Kxb6 Kd6 14. f4
Ke7 15. f5 Bc3 16. Kb7 Kd6 17. b6 Bd4 18. Ka6 Ke7 19. b7 Be5 20. Ka7 Bd4+ 21.
Ka8 Be5 22. b8=Q Bxb8 23. Kxb8 Kf7 24. Kb7 Kf6 25. Kc6 Ke5 26. Kc7 Kf4 27. f6
Kxg4 28. f7 Kf3 29. f8=Q+ Ke3 30. Qf1 Kd4 31. Qe2 Kc3 32. Kc6 Kb3 33. Qd2 Ka3
34. Kc5 Kb3 35. Kb5 Ka3 36. Kc4 Ka4 37. Qa2#) 1... Bxf4 (1... Bf6 2. Kd7 (2. a4
$6 Bc3 3. f5 Kg7 4. Ke7 Bf6+ 5. Ke6 Bc3 6. Bd1 Kf8 7. f6 Be1 8. Bh5 Bc3 9. Bg6
Bb4 10. Kd7 Ba5 11. Bh5 Be1 12. Kc6 Ba5 13. Kc7 Kg8 14. f7+ Kf8 15. f4 Ke7 16.
Kc6 Kf8 17. f5 Kg7 18. f6+ Kf8 19. Kc7 Bc3 20. Kxb6 Bd4 21. Kc6 Bxf6 22. Kxc5
Be5 23. b6 Ke7 24. Kc6 Bd4 25. a5 Bg7 26. f8=Q+ Kxf8 27. a6 Ke7 28. a7 Kf6 29.
a8=Q Kg5 30. Qg8 Kf4 31. Qxg7 Ke3 32. Kd5 Kf2 33. Kd4 Kf1 34. Ke3 Ke1 35. Qg1#)
2... Bc3 (2... Bd4 $5 3. Kc6 Bxf2 4. a4 h5 5. Kxb6 c4+ 6. Ka6 c3 7. f5 h4 8.
Be4 h3 9. b6 h2 10. Kb5 c2 11. b7 Bg3 12. Bxc2 h1=Q 13. b8=R+ Bxb8 14. Kc4 Qf1+
15. Kd5 Qg2+ 16. Be4 Qd2+ 17. Kc6 Qd6+ 18. Kb7 Qb4+ 19. Kc6 Qxe4+ 20. Kb6 Qe3+
21. Kc6 Qxb3 22. Kc5 Ba7+ 23. Kd6 Qxa4 24. Ke5 Kf7 25. Kd5 Bb6 26. f6 Kxf6 27.
Kd6 Qc4 28. Kd7 Qe6#) 3. Kc6 Ba5 4. b4 cxb4 5. Bb3+ Kg7 6. Kd5 Kf6 (6... h5 $5
7. f5 h4 8. Ke4 Kf6 9. Kf4 h3 10. Kg3 Kxf5 11. f3 Ke5 12. Kxh3 Kf4 13. Kg2 Ke5
14. Kg3 Kd4 15. f4 Kc5 16. f5 Kxb5 17. f6 Kc6 18. f7 b5 19. f8=Q Bc7+ 20. Kg4
Bh2 21. Qf6+ (21. Qe8+ $5 Kb6 22. Qg6+ (22. Qe6+ $5 Kc5 23. Qf5+ Kd6 24. Qd5+ (
24. Qf2 $5 Be5 25. Qb6+ Ke7 26. Kf5 Bh2 27. Qc5+ Bd6 28. Qa7+ Kd8 29. Ke6 Bc7
30. Qa8+ Bb8 31. Qxb8#) 24... Ke7 25. Kf5 Bc7 26. Qc5+ Kd8 27. Be6 Be5 28. Qc8+
Ke7 29. Qd7+ Kf8 30. Qf7#) 22... Ka5 23. Qc6 Be5 24. Qb7 Bd4 25. Kf5 Bc5 26.
Ke6 Bf2 27. Kd5 Bc5 28. Kc6 Bb6 29. Qxb6#) 21... Kc7 22. Qa6 Kd7 23. Kf5 Bg3
24. Be6+ Kc7 25. Bd5 Kd7 26. Qc6+ Ke7 27. Be6 Kf8 28. Qd7 b3 29. Qf7#) 7. Ke4
h5 8. f5 h4 9. Kf4 h3 10. Kg3 Kxf5 11. f3 Ke5 12. Kxh3 Kf4 13. Kg2 Ke3 14. Kg3
Kd4 15. f4 Kc5 16. f5 Kxb5 17. f6 Kc6 18. f7 b5 19. f8=Q Bc7+ 20. Kg2 Bd6 21.
Qe8+ Kc7 22. Qxb5 Kd8 23. Be6 Ke7 24. Qd7+ Kf6 25. Qxd6 Kg7 26. Bb3 Kh7 27.
Qe7+ Kg6 28. Bc2+ Kh5 29. Qf6 b3 30. Bd1#) 2. Kd7 Bd2 3. Kc6 Ba5 4. b4 cxb4 (
4... Bxb4 $6 5. Kxb6 Kf7 6. a4 Ke6 7. a5 Kd5 8. a6 c4 9. a7 Bc5+ 10. Ka6 Bxa7
11. Kxa7 Kd4 12. b6 Kc3 13. Bg6 h5 14. b7 h4 15. b8=Q h3 16. Qh8+ Kb3 17. Qxh3+
Ka2 18. Bf7 Kb2 19. Bxc4 Kb1 20. Qd3+ Kc1 21. Qc3+ Kb1 22. Qd2 Ka1 23. Qc1#) 5.
Bb3+ Kg7 6. Kd5 Kf6 7. Ke4 h5 (7... Kg5 $6 8. Ke5 h5 9. f4+ Kh6 10. f5 Kg7 11.
f6+ Kf8 12. Kf5 h4 13. Kg4 h3 14. Kxh3 Ke8 15. Kg4 Kd8 16. f7 Ke7 17. Kf5 Kf8
18. Ke6 Kg7 19. Ke7 Kg6 20. f8=Q Kg5 21. Qf3 Kg6 22. Qf6+ Kh7 23. Bc2+ Kg8 24.
Qf8#) 8. Kf4 Kg6 (8... h4 $5 9. f3 h3 10. Kg3 Ke5 11. Kxh3 Kf4 12. Kg2 Ke3 13.
Kg3 Kd4 14. f4 Kc5 15. f5 Kxb5 16. f6 Kc6 17. f7 b5 18. Kg4 Bd8 19. f8=Q Bc7
20. Qa8+ Kc5 21. Qb7 Bh2 22. Qa7+ Kc6 23. Kf5 Kd6 24. Qb6+ Ke7 25. Be6 Bd6 26.
Qa7+ Bc7 27. Qxc7+ Ke8 28. Qd7+ Kf8 29. Qf7#) 9. Ke5 h4 10. Kf4 Kh5 11. f3 $1
h3 12. Kg3 Kg5 13. Kxh3 Kf4 14. Kg2 Ke3 15. Kg3 Kd4 16. f4 Kc5 17. f5 Kxb5 18.
f6 Kc6 19. f7 b5 20. f8=Q Bc7+ 21. Kg4 Bh2 22. Qe8+ Kb6 23. Qg6+ (23. Qe6+ $5
Kc5 24. Qf5+ Kc6 25. Qc2+ Kb6 26. Qxh2 Kb7 27. Qd6 Kc8 28. Qc6+ Kd8 29. Qb7 Ke8
30. Qc7 Kf8 31. Qf7#) 23... Ka5 24. Qc6 Bg1 25. Kf3 Ba7 26. Ke4 Bf2 27. Kd3 Be1
28. Bc4 bxc4+ 29. Kxc4 b3 30. Qb5# 1-0
[/pgn]

In your line 1...Bf6 2.Kd7, I think 2...Bc3 and 3...Ba5 are mistakes because 4. b4! is a short mate. This 4.b4 is not easy to find for SF.
The most resistant line I found for black is : 1...Bf6 2.Kd7 Bd4 3.Kc6 with the 4 best moves :

Code: Select all

FEN: 6k1/8/1pK4p/1Pp5/3b1P2/1P6/P1B2P2/8 b - - 4 3

Stockfish_170713_matefinder:
...
 48/51	08:40	 9 296 781k	17 867k	+M25	3. ... Kf8 4.a4 Ke7 5.Kxb6 Kd6 6.a5 c4+ 7.Kb7 cxb3 8.Bxb3 Kc5 9.b6 Kb5 10.Kc7 Kxa5 11.b7 Bb6+ 12.Kc8 Ba7 13.b8Q Bxb8 14.Kxb8 Kb4 15.f5 Kxb3 16.f6 h5 17.f7 Kc4 18.f8Q Kd4 19.f4 Kc4 20.Qc8+ Kd4 21.f5 Ke5 22.Qe6+ Kf4 23.f6 Kf3 24.f7 Kf2 25.f8Q+ Kg2 26.Qe4+ Kg3 27.Qg8+ Kf2 28.Qgg2+
 48/51	08:40	 9 296 781k	17 867k	+M25	3. ... Kf7 4.a4 Ke6 5.Kxb6 Kd5 6.a5 c4+ 7.Kb7 cxb3 8.Bxb3+ Kc5 9.b6 Kb5 10.Kc7 Kxa5 11.b7 Bb6+ 12.Kc8 Ba7 13.b8Q Bxb8 14.Kxb8 Kb4 15.f5 Kxb3 16.f6 h5 17.f7 Kc4 18.f8Q Kd4 19.f4 Kc4 20.Qc8+ Kd4 21.f5 Ke5 22.Qe6+ Kf4 23.f6 Kf3 24.f7 Kf2 25.f8Q+ Kg2 26.Qe4+ Kg3 27.Qg8+ Kf2 28.Qgg2+
 49/65	08:40	 9 296 781k	17 867k	+M39	3. ... Bxf2 4.Kxb6 c4+ 5.Ka6 c3 6.b6 Be3 7.a4 h5 8.a5 h4 9.b7 Bxf4 10.Kb5 h3 11.a6 h2 12.a7 h1Q 13.b8Q+ Bxb8 14.axb8Q+ Kg7 15.Qg3+ Kf8 16.Qf4+ Kg7 17.Be4 Qh5+ 18.Kb6 c2 19.Bxc2 Qh3 20.Qe5+ Kg8 21.Qe4 Kh8 22.Qh7+ Qxh7 23.Bxh7 Kxh7 24.Kc6 Kg6 25.b4 Kf5 26.b5 Kg5 27.b6 Kf4 28.b7 Kg3 29.b8Q+ Kg2 30.Qb2+ Kg1 31.Qe5 Kh1 32.Qh8+ Kg1 33.Qh3 Kf2 34.Qg4 Ke3
 49/67	08:40	 9 296 781k	17 867k	+M40	3. ... h5 4.a4 Bxf2 5.Kxb6 c4+ 6.Ka6 c3 7.b6 Be3 8.a5 h4 9.b7 Bxf4 10.Kb5 h3 11.a6 h2 12.a7 h1Q 13.b8Q+ Bxb8 14.axb8Q+ Kg7 15.Qg3+ Kf8 16.Qf4+ Kg7 17.Be4 Qh5+ 18.Kb6 c2 19.Bxc2 Qh3 20.Qe5+ Kg8 21.Kc7 Qh6 22.Qe8+ Kg7 23.Qe7+ Kg8 24.Qh7+ Qxh7+ 25.Bxh7+ Kxh7 26.b4 Kh6 27.b5 Kh5 28.b6 Kg4 29.b7 Kg3 30.b8Q Kg2 31.Qh8 Kg1 32.Qh3 Kf2 33.Qh2+ Kf3 34.Kc8 Ke3 35.Qg3+ Kd4 36.Kc7

The distance to mate from the starting position is probably around 35-40 moves.

[peter]

The most resistant line I found for black is : 1...Bf6 2.Kd7 Bd4 3.Kc6
...

The distance to mate from the starting position is probably around 35-40 moves.

1...Bf6 2.Kd7 Bd4-line is in my .pgn above indeed a horrible blunder, copied output of a -# in there and didn't see it till now.


Here ist the corrected single one line:

[FEN "4K1k1/8/1p5p/1Pp3b1/8/1P3P2/P1B2P2/8 w - - 0 1"]

1. f4 Bf6 2. Kd7 Bd4 3. Kc6 Bxf2 4. a4 h5 5. Kxb6 c4+ 6. Kc6 c3 7. Kd5 h4 8. Kc4 h3 9. Kxc3 Kg7 10. Kc4 Kh6 11. a5 Kh5 12. Be4 Kg4 13. b6 Kxf4 14. Bd5 Ke5 15. b7 Ba7 16. b4 Kd6 17. b5 Kc7 18. b6+ Bxb6 19. axb6+ Kb8 20. Bh1 h2 21. Kd5 Kxb7 22. Kc5+ Kc8 23. Kd6 Kd8 24. b7 Ke8 25. Bd5 Kf8 26. b8=Q+ Kg7 27. Qg8+ Kf6 28. Be4 h1=R 29. Qg6#

Important is 6.Kc6! instead of Ka6?!, which indeed costs White some more moves.

Just to repair the shame-on-me-one, the latest whole hog again.



[pgn]
[Event "1st Prize, Sachova skladba "]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "Salai, Ladislav jr."]
[Black "10MV Eret90, Major Dual 1.Bd1"]
[Result "1-0"]
[Annotator "Martan,Peter"]
[SetUp "1"]
[FEN "4K1k1/8/1p5p/1Pp3b1/8/1P3P2/P1B2P2/8 w - - 0 1"]
[PlyCount "59"]
[EventDate "2013.??.??"]

1. f4 $1 (1. Kd7 $2 Bd2 2. Kc6 (2. f4 h5 3. Kc6 Ba5 4. Bd1 h4 5. b4 Bxb4 6.
Kxb6 c4 7. a4 h3) 2... Ba5 3. b4 $1 cxb4 4. Bb3+ Kg7 5. Kd5 Kf6 6. Ke4 h5 $1 7.
Kf4 Kg6 8. Ke5 h4 9. Kf4 Kh5) (1. Bd1 Kg7 (1... Bh4 $5 2. Kd7 Bxf2 3. Kc6 h5 4.
Kxb6 c4+ 5. Ka5 c3 6. Kb4 Be1 7. Kc4 h4 8. f4 Kf7 9. Kd3 Ke6 10. Bg4+ Kd5 11.
f5 c2 12. Kxc2 Ke5 13. a4 Kf6 14. b6 h3 15. Bxh3 Bg3 16. b7 Kg5 17. Kc3 Kh4 18.
Kc4 Be5 19. a5 Kg5 20. b4 Bb8 21. a6 Kf4 22. f6 Kg3 23. f7 Kxh3 24. f8=Q Ba7
25. b8=Q Bxb8 26. Qxb8 Kg4 27. a7 Kg5 28. Qg3+ Kf5 29. a8=Q Kf6 30. Qf8+ Ke6
31. Qgd6#) (1... Bd2 $5 2. f4 (2. Kd7 $2 {ZUS 1.Kd7}) 2... Bxf4 3. Kd7 Bd2 4.
Kc6 Ba5 5. b4 cxb4 6. Bb3+ {ZUS 1.f4 + 1 Zug}) (1... Bf4 $5 2. Kd7 Kf7 3. Kc6
Ke6 4. Kxb6) 2. Kd7 Bd2 3. f4 Kg6 4. Bg4 h5 5. f5+ Kf6 6. Bxh5 Kxf5 7. Kc6 Ba5
8. a3 Ke5 9. Bg4 Kf4 10. f3 Ke5 11. b4 cxb4 12. axb4 Bxb4 13. Kxb6 Kd6 14. f4
Ke7 15. f5 Bc3 16. Kb7 Kd6 17. b6 Bd4 18. Ka6 Ke7 19. b7 Be5 20. Ka7 Bd4+ 21.
Ka8 Be5 22. b8=Q Bxb8 23. Kxb8 Kf7 24. Kb7 Kf6 25. Kc6 Ke5 26. Kc7 Kf4 27. f6
Kxg4 28. f7 Kf3 29. f8=Q+ Ke3 30. Qf1 Kd4 31. Qe2 Kc3 32. Kc6 Kb3 33. Qd2 Ka3
34. Kc5 Kb3 35. Kb5 Ka3 36. Kc4 Ka4 37. Qa2#) (1. a4 c4 2. a5 Bf4) 1... Bxf4 (
1... Bf6 2. Kd7 (2. a4 $6 Bc3 3. f5 Kg7 4. Ke7 Bf6+ 5. Ke6 Bc3 6. Bd1 Kf8 7. f6
Be1 8. Bh5 Bc3 9. Bg6 Bb4 10. Kd7 Ba5 11. Bh5 Be1 12. Kc6 Ba5 13. Kc7 Kg8 14.
f7+ Kf8 15. f4 Ke7 16. Kc6 Kf8 17. f5 Kg7 18. f6+ Kf8 19. Kc7 Bc3 20. Kxb6 Bd4
21. Kc6 Bxf6 22. Kxc5 Be5 23. b6 Ke7 24. Kc6 Bd4 25. a5 Bg7 26. f8=Q+ Kxf8 27.
a6 Ke7 28. a7 Kf6 29. a8=Q Kg5 30. Qg8 Kf4 31. Qxg7 Ke3 32. Kd5 Kf2 33. Kd4 Kf1
34. Ke3 Ke1 35. Qg1#) 2... Bc3 (2... Bd4 $5 3. Kc6 Bxf2 (3... h5 4. a4 Bxf2 5.
Kxb6 c4+ {ZU}) 4. a4 h5 5. Kxb6 c4+ 6. Kc6 (6. Ka6 $6 c3 7. b6 Bg3 8. a5 h4 9.
b7 Bxf4 10. Kb5 h3 11. a6 h2 12. a7 h1=Q 13. b8=Q+ Bxb8 14. axb8=Q+ Kg7 15.
Qc7+ Kg8 16. Qc4+ Kf8 17. Qc5+ Kf7 18. b4 Qb7+ 19. Kc4 Qa6+ 20. b5 Qa2+ 21.
Kxc3 Qa1+ 22. Kb3 Qa5 23. Qc6 Qd2 24. Qc4+ Ke8 25. Bg6+ Kd8 26. Qd3+ Qxd3+ 27.
Bxd3 Kd7 28. Kc4 Kd6 29. Bc2 Ke5 30. b6 Kd6 31. Kb5 Ke7 32. b7 Kf6 33. b8=Q Kg5
34. Qe5+ Kh4 35. Qf4+ Kh3 36. Bf5+ Kg2 37. Be4+ Kg1 38. Qg3+ Kf1 39. Bd3#) 6...
c3 7. Kd5 h4 8. Kc4 h3 (8... Kf7 $5 9. Kxc3 Ke8 10. Kc4 Kd8 11. a5 Bg1 12. Be4
Be3 13. b4 Bxf4 14. b6 Be3 15. b5 h3 16. b7 Kc7 17. b6+ Bxb6 18. axb6+ Kb8 19.
Bh1 h2 20. Kd5 Kxb7 21. Kc5+ Kc8 22. Kd6 Kd8 23. b7 Ke8 24. Bd5 Kf8 25. b8=Q+
Kg7 26. Qg8+ Kf6 27. Be4 h1=R 28. Qg6#) 9. Kxc3 Kg7 10. Kc4 Kh6 11. a5 Kh5 12.
Be4 Kg4 13. b6 Kxf4 14. Bd5 Ke5 15. b7 Ba7 16. b4 Kd6 17. b5 Kc7 18. b6+ Bxb6
19. axb6+ Kb8 20. Bh1 h2 21. Kd5 Kxb7 22. Kc5+ Kc8 23. Kd6 Kd8 24. b7 Ke8 25.
Bd5 Kf8 26. b8=Q+ Kg7 27. Qg8+ Kf6 28. Be4 h1=R 29. Qg6#) 3. Kc6 Ba5 4. b4 cxb4
5. Bb3+ Kg7 6. Kd5 Kf6 (6... h5 $5 7. f5 h4 8. Ke4 Kf6 9. Kf4 h3 10. Kg3 Kxf5
11. f3 Ke5 12. Kxh3 Kf4 13. Kg2 Ke5 14. Kg3 Kd4 15. f4 Kc5 16. f5 Kxb5 17. f6
Kc6 18. f7 b5 19. f8=Q Bc7+ 20. Kg4 Bh2 21. Qf6+ (21. Qe8+ $5 Kb6 22. Qg6+ (22.
Qe6+ $5 Kc5 23. Qf5+ Kd6 24. Qd5+ (24. Qf2 $5 Be5 25. Qb6+ Ke7 26. Kf5 Bh2 27.
Qc5+ Bd6 28. Qa7+ Kd8 29. Ke6 Bc7 30. Qa8+ Bb8 31. Qxb8#) 24... Ke7 25. Kf5 Bc7
26. Qc5+ Kd8 27. Be6 Be5 28. Qc8+ Ke7 29. Qd7+ Kf8 30. Qf7#) 22... Ka5 23. Qc6
Be5 24. Qb7 Bd4 25. Kf5 Bc5 26. Ke6 Bf2 27. Kd5 Bc5 28. Kc6 Bb6 29. Qxb6#)
21... Kc7 22. Qa6 Kd7 23. Kf5 Bg3 24. Be6+ Kc7 25. Bd5 Kd7 26. Qc6+ Ke7 27. Be6
Kf8 28. Qd7 b3 29. Qf7#) 7. Ke4 h5 8. f5 h4 9. Kf4 h3 10. Kg3 Kxf5 11. f3 Ke5
12. Kxh3 Kf4 13. Kg2 Ke3 14. Kg3 Kd4 15. f4 Kc5 16. f5 Kxb5 17. f6 Kc6 18. f7
b5 19. f8=Q Bc7+ 20. Kg2 Bd6 21. Qe8+ Kc7 22. Qxb5 Kd8 23. Be6 Ke7 24. Qd7+ Kf6
25. Qxd6 Kg7 26. Bb3 Kh7 27. Qe7+ Kg6 28. Bc2+ Kh5 29. Qf6 b3 30. Bd1#) 2. Kd7
Bd2 3. Kc6 Ba5 4. b4 cxb4 (4... Bxb4 $6 5. Kxb6 Kf7 6. a4 Ke6 7. a5 Kd5 8. a6
c4 9. a7 Bc5+ 10. Ka6 Bxa7 11. Kxa7 Kd4 12. b6 Kc3 13. Bg6 h5 14. b7 h4 15.
b8=Q h3 16. Qh8+ Kb3 17. Qxh3+ Ka2 18. Bf7 Kb2 19. Bxc4 Kb1 20. Qd3+ Kc1 21.
Qc3+ Kb1 22. Qd2 Ka1 23. Qc1#) 5. Bb3+ Kg7 6. Kd5 Kf6 7. Ke4 h5 (7... Kg5 $6 8.
Ke5 h5 9. f4+ Kh6 10. f5 Kg7 11. f6+ Kf8 12. Kf5 h4 13. Kg4 h3 14. Kxh3 Ke8 15.
Kg4 Kd8 16. f7 Ke7 17. Kf5 Kf8 18. Ke6 Kg7 19. Ke7 Kg6 20. f8=Q Kg5 21. Qf3 Kg6
22. Qf6+ Kh7 23. Bc2+ Kg8 24. Qf8#) 8. Kf4 Kg6 (8... h4 $5 9. f3 h3 10. Kg3 Ke5
11. Kxh3 Kf4 12. Kg2 Ke3 13. Kg3 Kd4 14. f4 Kc5 15. f5 Kxb5 16. f6 Kc6 17. f7
b5 18. Kg4 Bd8 19. f8=Q Bc7 20. Qa8+ Kc5 21. Qb7 Bh2 22. Qa7+ Kc6 23. Kf5 Kd6
24. Qb6+ Ke7 25. Be6 Bd6 26. Qa7+ Bc7 27. Qxc7+ Ke8 28. Qd7+ Kf8 29. Qf7#) 9.
Ke5 h4 10. Kf4 Kh5 11. f3 $1 h3 12. Kg3 Kg5 13. Kxh3 Kf4 14. Kg2 Ke3 15. Kg3
Kd4 16. f4 Kc5 17. f5 Kxb5 18. f6 Kc6 19. f7 b5 20. f8=Q Bc7+ 21. Kg4 Bh2 22.
Qe8+ Kb6 23. Qg6+ (23. Qe6+ $5 Kc5 24. Qf5+ Kc6 25. Qc2+ Kb6 26. Qxh2 Kb7 27.
Qd6 Kc8 28. Qc6+ Kd8 29. Qb7 Ke8 30. Qc7 Kf8 31. Qf7#) 23... Ka5 24. Qc6 Bg1
25. Kf3 Ba7 26. Ke4 Bf2 27. Kd3 Be1 28. Bc4 bxc4+ 29. Kxc4 b3 30. Qb5# 1-0
[/pgn]

[Vinvin]

The most resistant line I found for black is : 1...Bf6 2.Kd7 Bd4 3.Kc6
...

The distance to mate from the starting position is probably around 35-40 moves.

1...Bf6 2.Kd7 Bd4-line is in my .pgn above indeed a horrible blunder, copied output of a -# in there and didn't see it till now.


Here ist the corrected single one line:

[FEN "4K1k1/8/1p5p/1Pp3b1/8/1P3P2/P1B2P2/8 w - - 0 1"]

1. f4 Bf6 2. Kd7 Bd4 3. Kc6 Bxf2 4. a4 h5 5. Kxb6 c4+ 6. Kc6 c3 7. Kd5 h4 8. Kc4 h3 9. Kxc3 Kg7 10. Kc4 Kh6 11. a5 Kh5 12. Be4 Kg4 13. b6 Kxf4 14. Bd5 Ke5 15. b7 Ba7 16. b4 Kd6 17. b5 Kc7 18. b6+ Bxb6 19. axb6+ Kb8 20. Bh1 h2 21. Kd5 Kxb7 22. Kc5+ Kc8 23. Kd6 Kd8 24. b7 Ke8 25. Bd5 Kf8 26. b8=Q+ Kg7 27. Qg8+ Kf6 28. Be4 h1=R 29. Qg6#

Important is 6.Kc6! instead of Ka6?!, which indeed costs White some more moves.

Just to repair the shame-on-me-one, the latest whole hog again.



[pgn]
[Event "1st Prize, Sachova skladba "]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "Salai, Ladislav jr."]
[Black "10MV Eret90, Major Dual 1.Bd1"]
[Result "1-0"]
[Annotator "Martan,Peter"]
[SetUp "1"]
[FEN "4K1k1/8/1p5p/1Pp3b1/8/1P3P2/P1B2P2/8 w - - 0 1"]
[PlyCount "59"]
[EventDate "2013.??.??"]

1. f4 $1 (1. Kd7 $2 Bd2 2. Kc6 (2. f4 h5 3. Kc6 Ba5 4. Bd1 h4 5. b4 Bxb4 6.
Kxb6 c4 7. a4 h3) 2... Ba5 3. b4 $1 cxb4 4. Bb3+ Kg7 5. Kd5 Kf6 6. Ke4 h5 $1 7.
Kf4 Kg6 8. Ke5 h4 9. Kf4 Kh5) (1. Bd1 Kg7 (1... Bh4 $5 2. Kd7 Bxf2 3. Kc6 h5 4.
Kxb6 c4+ 5. Ka5 c3 6. Kb4 Be1 7. Kc4 h4 8. f4 Kf7 9. Kd3 Ke6 10. Bg4+ Kd5 11.
f5 c2 12. Kxc2 Ke5 13. a4 Kf6 14. b6 h3 15. Bxh3 Bg3 16. b7 Kg5 17. Kc3 Kh4 18.
Kc4 Be5 19. a5 Kg5 20. b4 Bb8 21. a6 Kf4 22. f6 Kg3 23. f7 Kxh3 24. f8=Q Ba7
25. b8=Q Bxb8 26. Qxb8 Kg4 27. a7 Kg5 28. Qg3+ Kf5 29. a8=Q Kf6 30. Qf8+ Ke6
31. Qgd6#) (1... Bd2 $5 2. f4 (2. Kd7 $2 {ZUS 1.Kd7}) 2... Bxf4 3. Kd7 Bd2 4.
Kc6 Ba5 5. b4 cxb4 6. Bb3+ {ZUS 1.f4 + 1 Zug}) (1... Bf4 $5 2. Kd7 Kf7 3. Kc6
Ke6 4. Kxb6) 2. Kd7 Bd2 3. f4 Kg6 4. Bg4 h5 5. f5+ Kf6 6. Bxh5 Kxf5 7. Kc6 Ba5
8. a3 Ke5 9. Bg4 Kf4 10. f3 Ke5 11. b4 cxb4 12. axb4 Bxb4 13. Kxb6 Kd6 14. f4
Ke7 15. f5 Bc3 16. Kb7 Kd6 17. b6 Bd4 18. Ka6 Ke7 19. b7 Be5 20. Ka7 Bd4+ 21.
Ka8 Be5 22. b8=Q Bxb8 23. Kxb8 Kf7 24. Kb7 Kf6 25. Kc6 Ke5 26. Kc7 Kf4 27. f6
Kxg4 28. f7 Kf3 29. f8=Q+ Ke3 30. Qf1 Kd4 31. Qe2 Kc3 32. Kc6 Kb3 33. Qd2 Ka3
34. Kc5 Kb3 35. Kb5 Ka3 36. Kc4 Ka4 37. Qa2#) (1. a4 c4 2. a5 Bf4) 1... Bxf4 (
1... Bf6 2. Kd7 (2. a4 $6 Bc3 3. f5 Kg7 4. Ke7 Bf6+ 5. Ke6 Bc3 6. Bd1 Kf8 7. f6
Be1 8. Bh5 Bc3 9. Bg6 Bb4 10. Kd7 Ba5 11. Bh5 Be1 12. Kc6 Ba5 13. Kc7 Kg8 14.
f7+ Kf8 15. f4 Ke7 16. Kc6 Kf8 17. f5 Kg7 18. f6+ Kf8 19. Kc7 Bc3 20. Kxb6 Bd4
21. Kc6 Bxf6 22. Kxc5 Be5 23. b6 Ke7 24. Kc6 Bd4 25. a5 Bg7 26. f8=Q+ Kxf8 27.
a6 Ke7 28. a7 Kf6 29. a8=Q Kg5 30. Qg8 Kf4 31. Qxg7 Ke3 32. Kd5 Kf2 33. Kd4 Kf1
34. Ke3 Ke1 35. Qg1#) 2... Bc3 (2... Bd4 $5 3. Kc6 Bxf2 (3... h5 4. a4 Bxf2 5.
Kxb6 c4+ {ZU}) 4. a4 h5 5. Kxb6 c4+ 6. Kc6 (6. Ka6 $6 c3 7. b6 Bg3 8. a5 h4 9.
b7 Bxf4 10. Kb5 h3 11. a6 h2 12. a7 h1=Q 13. b8=Q+ Bxb8 14. axb8=Q+ Kg7 15.
Qc7+ Kg8 16. Qc4+ Kf8 17. Qc5+ Kf7 18. b4 Qb7+ 19. Kc4 Qa6+ 20. b5 Qa2+ 21.
Kxc3 Qa1+ 22. Kb3 Qa5 23. Qc6 Qd2 24. Qc4+ Ke8 25. Bg6+ Kd8 26. Qd3+ Qxd3+ 27.
Bxd3 Kd7 28. Kc4 Kd6 29. Bc2 Ke5 30. b6 Kd6 31. Kb5 Ke7 32. b7 Kf6 33. b8=Q Kg5
34. Qe5+ Kh4 35. Qf4+ Kh3 36. Bf5+ Kg2 37. Be4+ Kg1 38. Qg3+ Kf1 39. Bd3#) 6...
c3 7. Kd5 h4 8. Kc4 h3 (8... Kf7 $5 9. Kxc3 Ke8 10. Kc4 Kd8 11. a5 Bg1 12. Be4
Be3 13. b4 Bxf4 14. b6 Be3 15. b5 h3 16. b7 Kc7 17. b6+ Bxb6 18. axb6+ Kb8 19.
Bh1 h2 20. Kd5 Kxb7 21. Kc5+ Kc8 22. Kd6 Kd8 23. b7 Ke8 24. Bd5 Kf8 25. b8=Q+
Kg7 26. Qg8+ Kf6 27. Be4 h1=R 28. Qg6#) 9. Kxc3 Kg7 10. Kc4 Kh6 11. a5 Kh5 12.
Be4 Kg4 13. b6 Kxf4 14. Bd5 Ke5 15. b7 Ba7 16. b4 Kd6 17. b5 Kc7 18. b6+ Bxb6
19. axb6+ Kb8 20. Bh1 h2 21. Kd5 Kxb7 22. Kc5+ Kc8 23. Kd6 Kd8 24. b7 Ke8 25.
Bd5 Kf8 26. b8=Q+ Kg7 27. Qg8+ Kf6 28. Be4 h1=R 29. Qg6#) 3. Kc6 Ba5 4. b4 cxb4
5. Bb3+ Kg7 6. Kd5 Kf6 (6... h5 $5 7. f5 h4 8. Ke4 Kf6 9. Kf4 h3 10. Kg3 Kxf5
11. f3 Ke5 12. Kxh3 Kf4 13. Kg2 Ke5 14. Kg3 Kd4 15. f4 Kc5 16. f5 Kxb5 17. f6
Kc6 18. f7 b5 19. f8=Q Bc7+ 20. Kg4 Bh2 21. Qf6+ (21. Qe8+ $5 Kb6 22. Qg6+ (22.
Qe6+ $5 Kc5 23. Qf5+ Kd6 24. Qd5+ (24. Qf2 $5 Be5 25. Qb6+ Ke7 26. Kf5 Bh2 27.
Qc5+ Bd6 28. Qa7+ Kd8 29. Ke6 Bc7 30. Qa8+ Bb8 31. Qxb8#) 24... Ke7 25. Kf5 Bc7
26. Qc5+ Kd8 27. Be6 Be5 28. Qc8+ Ke7 29. Qd7+ Kf8 30. Qf7#) 22... Ka5 23. Qc6
Be5 24. Qb7 Bd4 25. Kf5 Bc5 26. Ke6 Bf2 27. Kd5 Bc5 28. Kc6 Bb6 29. Qxb6#)
21... Kc7 22. Qa6 Kd7 23. Kf5 Bg3 24. Be6+ Kc7 25. Bd5 Kd7 26. Qc6+ Ke7 27. Be6
Kf8 28. Qd7 b3 29. Qf7#) 7. Ke4 h5 8. f5 h4 9. Kf4 h3 10. Kg3 Kxf5 11. f3 Ke5
12. Kxh3 Kf4 13. Kg2 Ke3 14. Kg3 Kd4 15. f4 Kc5 16. f5 Kxb5 17. f6 Kc6 18. f7
b5 19. f8=Q Bc7+ 20. Kg2 Bd6 21. Qe8+ Kc7 22. Qxb5 Kd8 23. Be6 Ke7 24. Qd7+ Kf6
25. Qxd6 Kg7 26. Bb3 Kh7 27. Qe7+ Kg6 28. Bc2+ Kh5 29. Qf6 b3 30. Bd1#) 2. Kd7
Bd2 3. Kc6 Ba5 4. b4 cxb4 (4... Bxb4 $6 5. Kxb6 Kf7 6. a4 Ke6 7. a5 Kd5 8. a6
c4 9. a7 Bc5+ 10. Ka6 Bxa7 11. Kxa7 Kd4 12. b6 Kc3 13. Bg6 h5 14. b7 h4 15.
b8=Q h3 16. Qh8+ Kb3 17. Qxh3+ Ka2 18. Bf7 Kb2 19. Bxc4 Kb1 20. Qd3+ Kc1 21.
Qc3+ Kb1 22. Qd2 Ka1 23. Qc1#) 5. Bb3+ Kg7 6. Kd5 Kf6 7. Ke4 h5 (7... Kg5 $6 8.
Ke5 h5 9. f4+ Kh6 10. f5 Kg7 11. f6+ Kf8 12. Kf5 h4 13. Kg4 h3 14. Kxh3 Ke8 15.
Kg4 Kd8 16. f7 Ke7 17. Kf5 Kf8 18. Ke6 Kg7 19. Ke7 Kg6 20. f8=Q Kg5 21. Qf3 Kg6
22. Qf6+ Kh7 23. Bc2+ Kg8 24. Qf8#) 8. Kf4 Kg6 (8... h4 $5 9. f3 h3 10. Kg3 Ke5
11. Kxh3 Kf4 12. Kg2 Ke3 13. Kg3 Kd4 14. f4 Kc5 15. f5 Kxb5 16. f6 Kc6 17. f7
b5 18. Kg4 Bd8 19. f8=Q Bc7 20. Qa8+ Kc5 21. Qb7 Bh2 22. Qa7+ Kc6 23. Kf5 Kd6
24. Qb6+ Ke7 25. Be6 Bd6 26. Qa7+ Bc7 27. Qxc7+ Ke8 28. Qd7+ Kf8 29. Qf7#) 9.
Ke5 h4 10. Kf4 Kh5 11. f3 $1 h3 12. Kg3 Kg5 13. Kxh3 Kf4 14. Kg2 Ke3 15. Kg3
Kd4 16. f4 Kc5 17. f5 Kxb5 18. f6 Kc6 19. f7 b5 20. f8=Q Bc7+ 21. Kg4 Bh2 22.
Qe8+ Kb6 23. Qg6+ (23. Qe6+ $5 Kc5 24. Qf5+ Kc6 25. Qc2+ Kb6 26. Qxh2 Kb7 27.
Qd6 Kc8 28. Qc6+ Kd8 29. Qb7 Ke8 30. Qc7 Kf8 31. Qf7#) 23... Ka5 24. Qc6 Bg1
25. Kf3 Ba7 26. Ke4 Bf2 27. Kd3 Be1 28. Bc4 bxc4+ 29. Kxc4 b3 30. Qb5# 1-0
[/pgn]

I've not seen the line "1. f4 Bf6 2. Kd7 Bd4". Arena is not very clear about sub-variations.
Thanks for you accurate analyze !
I thought SF-MF was more accurate for long mates, but it can be off by 10 moves

[peter]

Thanks for you accurate analyze !

You're welcome!

I thought SF-MF was more accurate for long mates, but it can be off by 10 moves

10 moves too long lines to be rather sure of not getting too short ones for 3 to 5 times longer distances to mate, all in all seems not so bad to me.