| LoveThatJoker: A complicated battle! I gave the final position to Stockfish so it would clearly explain to me why Black resigned. As it turns out, the engine found a good practical try for Black to save the game had White played 41. a7. Here is its output:
<41. a7>
click for larger viewA) 41...h5! 42. Qa6 Kg5 43. Qd3 f5 44. Be7+ Kh6 45. Qxe4 fxe4 46. Bc5 Kg5 47. Be3+ Kf6 48. Bc4 Ba8 49. h4 Ke7 50. Kf2 Bd6 51. Bb3 Ke8 52. Bc2 Kd8 53. Ba4 Ke7 54. Bg5+ Kf7 55. Bb5 Bc5+ 56. Be3 Be7 57. g3 Bd6 58. Ba4 Ke7 59. Bb5 Kf8 60. Bc4 Ke7 61. Bg5+ Ke8 62. Bf4 Bc5+ 63. Be3 Bd6 64. Bg5 Bc5+ 65. Be3 <+2.42 at a Depth of 23> B) 41...Kf4 42. Qd8 Bd4+ 43. Bxd4 Qxd4+ 44. Kh2 Qxa7 45. Qxd5 f5 46. h4 Qe3 47. Qd6+ Ke4 48. Qe7+ Kd4 49. Qb4+ Ke5 50. g3 Qf2+ 51. Bg2 Qa7 52. Bb7 Qf2+ 53. Kh3 Qe3 54. Qe7+ Kd4 55. Qxh7 Qe6 56. Qh8+ Kd3 <+4.44 at a Depth of 23> As can be seen from line 'A', White definitely has the better of it, but proving the win for him won't be that easy! LTJ
PS. While Stockfish was considering the final position, I calculated an important and winning tactic available to White after 41. a7 Qf4?? Analysis Diagram - Position after 41. a7 Qf4??
click for larger view42. g4+! Ke4 (42...Kg5 43. Be3 and Black loses his Queen) 43. Qb1+ Kf3 44. Qd1+ Kg3 (44...Ke4 45. Qd3#/Bd3#) 45. Qe1+ Kf3 (45...Qf2+ 46. Qxf2#) 46. Bg2# | 
