Knight and Pawns against Bishop

B. Sorensen - J. Kolbak European Senior Championship 65+, 13 June 2016 1.Nf3 Nf6 2.c4 d6 3.d4 Bf5 4.Nc3 h6 5.e3 Nbd7 6.Bd3 Bxd3 7.Qxd3 e5 8.0-0 Be7 9.h3 0-0 10.e4 Re8 11.Qc2 Bf8 12.d5 c6 13.Be3 Qa5 14.a3 cxd5 15.cxd5 Rec8 16.Rfc1 Qd8 17.Qe2 Nc5 18.Nd2 a5 19.Bxc5 Rxc5 20.Na4 Rxc1+ 21.Rxc1 Rc8 22.Rxc8 Qxc8 23.Nc3 Be7 24.Qb5 Bd8 25.Nc4 Qc7 26.g3 Kf8 27.Kg2 Ke7 28.b4 Nd7 29.bxa5 Nc5 30.Nb6 h5 31.Qe2 Nb3 32.Nd1 Nxa5 33.Na4 Qc4 34.Nac3 Qxe2 35.Nxe2 Bb6 36.Nec3 Bc5 37.a4 Nc4 38.Kf3 g6 39.Ke2 f5 40.Kd3 Na5 41.Nb5 fxe4+ 42.Kxe4 Nc4 43.Kd3 Nb6 44.Nbc3 Bb4 45.Kc2 Bc5 46.Kb3 Na8 47.Kc4 Nc7 48.Ne4 Bd4 49.f4 Ba1 50.Ng5 exf4 51.gxf4 Bf6 52.Nf2 Kd7 53.Nfe4 Ba1 54.f5 gxf5 55.Ng3 Be5 56.Nxf5 Ne8 57.Nf3 Bf4 58.N3d4 Nf6 59.Ne6 Be5 60.Nf8+ Kc7 61.Ng6 Nd7 62.a5 Bf6 63.Ng3 h4 64.Nf5 Ne5+ 65.Nxe5 dxe5 66.Kc5 Bd8 67.Ne3 Be7+ 68.Kb5 e4 69.Kc4 Bf6 70.Nf5 Kd7 71.Kc5 Bd8 72.Kd4 Bxa5 73.Nxh4 Bd8 74.Nf5 b5 75.Kxe4 7-man ending starts here. 75...Bf6 [Probe says 75...Ba5 also holds] 76.Kd3 Be5 77.h4 77...Ke8? It may seem natural to move towards the advancing h-pawn but the B should be able to deal with that. The K should stay close to the d-pawn. Black's problem is that his b-pawn will probably fall sooner or later. Only three moves draw: [77...Bf6 ; 77...Bh8 ; 77...Kc7 ] 78.Nd4? [White can mate in 44 moves starting 78.h5! Probe's main line continues 78...Kf7 79.Ke4 Bc3 80.Nd4 Ba5 (80...b4 81.d6 Be1 82.d7 Bh4 83.Nf5 b3 84.Kd3!! (After 84 Nxh4 Black would promote with check and so could hold the draw despite being N and P down at the start.) 81.Nxb5 Kf6 82.Kf4 Bd2+ 83.Kg4 Bc1 84.d6 Bb2 85.Nc7 Bc1 86.Kh3 Paradoxical waiting move; Nb5, Kh4 and Kf3 also win but are two moves slower.] 78...Kf7 [78...b4 also sufficient to draw with best play.] 79.Nxb5 Now it is N+2P v B 79...Kg6 [79...Bg3 also holds, driving the h-pawn nearer to Black's K.] 80.Nd4 80...Bf6 [80...Bd6 and; 80...Kh5 also hold] 81.Nf3 Kh5?? The h-pawn cannot be won because the N cannot be driven from f3. To chase the N from g4, it would anyway be just as good to approach via f5. Therefore it should be obvious that the correct defence is [81...Kf5 restricting the white K and staying in touch with both pawns] 82.Ke4 White can also win with the immediate pawn advance: [82.d6 Bd8 (82...Kg4 83.Ke4 transposes to the game.) 83.d7 Be7 84.Kd4 Kg4 If Black only moves the B, the WK will eventually reach a square where it can capture the B after d8Q and the BK can never take the N without leaving the square of the h-pawn. 85.Ne5+! Exploting the knight fork on g6 is by far the quickest although Kd5, Ke5, Ke4 and Kc4 all preserve the win. 85...Kf5 86.h5 Kg5 (86...Bd8 87.h6 Kf6 88.Kd5 and BK cannot get to the h-pawn) 87.Nc6 BK is in the way of its B, shortening the critical diagonal. 87...Bf6+ 88.Kd5 This would be won without the h-pawn? 88...Kxh5 (88...Kf5 89.h6 Kg6 90.Ke6 Bh4 91.Ne7+ ) 89.Ke6 Bh4 90.Ne7 ] 82...Kg4 White also mates in 26 after [82...Be7 83.Ke5 and BK is a bystander: 83...Bd8 84.d6 Bb6 85.Ke6 Ba5 86.d7 Bd8 87.Kf7 Bc7 88.Ke7 ] 83.d6[] Bd8 84.d7 Bb6 85.Kd5 Kf5 The black king comes back but it's too late. [85...Bd8 86.Ke6 or 86 Kc6] 86.Kc6 Mates in 21, but the fastest mates in 15: [86.Nd4+ Kf6 87.Ne6 Ba5 88.h5 White mustn't liquidate and allow a drawn RP ending. 88...Bb6 89.h6 The h-pawn is used as a decoy to drive BK away. 89...Kg6 90.Kd6 and Nc7 wins.] 86...Ba5 [86...Bd8 prolongs the agony by three moves: 87.h5 Kf6 88.h6 Kg6 89.Ne5+! exploiting a fork possibility 89...Kf6 (89...Kh7 90.Kd6 Ba5 91.Kc5 Bd8 (91...Kxh6 92.Kb5 Bc7 93.Kc6 Ba5 94.Kb7 to control all four squares on the diagonal; a bishop needs five to draw. 94...Kg7 95.Nc6 ) 92.Nc6 Bc7 93.Kb5 Kxh6 94.Ka6 Kg7 95.Kb7+- ) ] 87.Kb7 Good enough but quicker is [87.Nd4+ Kf6 88.Kb7 Ke7 89.Kc8! 89 Nc6+ and Nxa5 does win with care but the mate is slower. 89...Bb6 90.Nb5 threatening Nc7 90...Bd8 91.h5 etc.] 87...Ke6 88.Kc8 Ke7 [88...Kd6 89.h5 (Or 89 Nd2) 89...Ke6 to get back in the square 90.h6 Kf6 91.Nd2 Kg6 92.Nc4 ] 89.Ne5 Kf6 90.Nc4 1-0