Knight v Bishop (part 13)

White has just captured on f3 in Pedro Ramon Martinez Reyes (2246) - Spanton (1995), Gibraltar 2014. Who stands better, and by how much?

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White is winning, according to Stockfish12; has a slight edge, according to Komodo11.01. The latter verdict is probably correct.

28...Kf7 29.h4 g6 30.Kg4 h5+ 31.Kf3 Be7 32.g3 e5!?

This is the engines' choice. It puts a central pawn on the same colour-complex as the bishop but opens a way for the black king to advance.

33.Nc3 Ke6 34.Ke4 Bc5 35.Nd1 Kf6 36.Ne3 Ke6 37.c3 b6 38.d4!?

Stockfish12 strongly dislikes this, but it is hard to see how else White makes progress.

38...exd4 39.cxd4

Now White is the player with the isolani, but White has created a 3-2 kingside majority.

39...Be7 40.Nc4 Bf6?!

The engines prefer 40...Bd6, and if 41.f4, which seems a good answer to the text, 41...c5 42.d5+ Kf6 43.Ne5 Bxe5 44.fxe5+ Ke7 appears to hold, although Komodo11.01 for a long time reckons White is winning.

41.Ne5?!

Almost certainly stronger is 41.f4, which threatens the winning 42.Ne5 Bxe5 43.fxe5! (43.dxe5 only draws), which is a winning pawn-ending thanks to the white king having an invasion route via f4. The engines reckon Black's best chance is 41...c5, but the simple reply 42.dxc5 wins as 42...bxc5 is met by 43.Ne5, when either the g6 pawn falls or White gets a passed pawn after 43...Bxe5 44.fxe5.

41...Bxe5 42.dxe5

White is winning, according to Komodo11.01; has a slight edge, according to Stockfish12. This time Stockfish12 is probably correct.

42...c5 43.f3 b5 44.g4

Komodo11.01 reckons White wins with 44.a3, meeting Stockfish12's 44...a6! with 45.g4, but then Stockfish12's 45...c4! 46.bxc4 hxg4 draws, as Komodo11.01 comes to see after 47.fxg4 Kd4 48.c3 Kxc3 Kxe5. In this line, the try 47...h5 48.Kd3 gxh5 49.gxh5 Kxe5 50.Kxc3 is also a draw.

44...hxg4?

44...c4 had to be played, after which 45.bxc4 hxg4! 46.fxg4 bxc4 is drawn, as in the second part of the previous note.

45.fxg4 a5?!

Pushing the c pawn no longer draws as White can ignore it and instead create a second passed pawn of his own, eg 45...c4 46.h5 c3 47.Kd3 gxh5 (47...b4 48.h6 Kf7 49.e6+!) 48.gxh5 Kxe5 49.b4 Kf5 50.Kxc3 Kg5 51.Kd4 Kxh5 52.Kc5 Kg4 53.Kxb5 Kf4 54.Kc6 Ke5 55.Kxc7 Kd5 56.Kb7 Kc4 57.a3 etc. However, it may be it is easier for White to go wrong than is the case after the text.

46.h5 gxh5 47.gxh5 c4 48.bxc4 b4 49.h6 1-0