Instructive Ending

PLAYED on board two (of six) for Hastings & St Leonards away to Rainham in the 140-average section of the Kent League last night.

White has just captured a rook on c1 and offered a draw in Andrew Waters (154) - Spanton (170)

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Black has a very small edge thanks to having the better bishop, but the difference is well within chess's drawing margin.
19...f5 20.Kf1 Nf6 21.Ne5 Ne4 22.f3 Nd6 23.Ke2 Bxe5?
Unbalancing the position, but in White's favour. I should have settled for a draw, or at least kept manoeuvring, rather than give White a passed pawn and create unbalanced pawn-majorities with White having the only bishop.
24.dxe5 Nc4 25.f4
Stockfish10 and Komodo10 give 25.e6!? Kf8 26.Bg5!?, when 26...Nxb2 27.Ke3 h6 28.Bf6 Nc4+ 29.Kd4 seems promising for White, but is not clear.
25...Kf7
The engines slightly prefer 25...Na5!?, eg 26.Kd3 Nc6, when Black may well be holding.
26.Kd3 Ke6 27.Kd4 Nb6 28.b3 Nc8?!
Probably better is 28...Nd7 and if, as in the game, 29.Ba3, then 29...Nb8 is equal, according to the engines. However, they reckon 29.b4 gives White an edge, eg 29...Nb6 30.Kd3 a6 (or 30...Nd7 31.Be3 a6 32.a4) 31.Kd4. In all lines Black is in danger of ending up in zugzwang as the black king is tied to defending d5 and the black knight has limited manoeuvrability.
29.Ba3 Nb6 30.Bb4 Nd7 31.Bd6 Nb6 32.a4 Nc8 33.Ba3 b6 34.Bb4 a5 35.Ba3?
The engines reckon White has a large advantage after 35.Bd2, one sample line running 35...Ne7 36.Be3 Nc8 (with the bishop on e3, rather than a3 as in the game, the move 36...Nc6+ drops the b6 pawn) 37.Kc3 Kd7 38.Bf2 Ke6 39.b4 axb4+ 40.Kxb4 Kd7 41.Kb5 Kc7 42.Ka6 Kc6 43.e6 Kc7 44.Bd4 Kc6 45.Be5 Ne7 46.Bf6 Nc8 47.e7 Kd7 48.Kb7 Nxe7 49.Kxb6, when the white outside passed pawn should settle it. After the text, the game is equal.
35...Na7 36.Bd6
36.Bc1 Nc6+ 37.Kc3 gives Black time to protect b6 with the king, eg 37...Kd7 38.Be3 Kc7. White could try 39.e6, but 39...Kd6 40.Bxb6 Kxe6 41.Bc5 Kd7 42.b4 axb4+ 43.Bxb4 Kc7 seems fine for Black.
36...Nc6+ 37.Kc3 Kd7 38.g4?
This turns a drawn position into a losing one.
38...fxg4 39.hxg4 h5 40.gxh5 gxh5 41.f5 h4 42.Bf8 h3?
Simply winning is 42...Nxe5, eg 43.Bh6 h3 44.Bf4 Nf3 etc.
43.e6+ Kc7 44.Bh6 h2?
Now Black turns a draw into a loss.
44...Kd6 45.Bf4+ Ke7 46.Bg5+ Kd6 47.Bf4+ etc draws.
45.Bf4+ Kd8 46.Bxh2
The game finished:
46...Ke7 47.Bg3 Kf6 48.Bh4+ Kxf5 49.e7 Nxe7 50.Bxe7 Ke5 1-0
Rainham won the match 4-2.