Opposite Exceptions (part seven)

Black has just captured on f7 in David JR Barnes (154) - Spanton (172), Kent League 170 Average Final 2011. How big is Black's advantage?

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The position is dead-equal, according to Stockfish12, but Komodo11.01 gives Black a slight edge.

41.dxe4

DB said afterwards he thought there was no way Black could win from here.

41...a4 42.h4 Bxc4 43.Kf3 Ke6 44.Kf4 Bd3 45.Bd2 Kd6 46.Bc3 h6

Both engines now rate the position as equal. I see from my original notes that Rybka3 reckoned 46...c4 gives Black a slight edge, but Stockfish12 and Komodo11.01 disagree.

47.Bd2!?

I expected 47.Bg7, which is marginally preferred by Komodo11.01 (Stockfish12 reckons the position is dead-equal after either move). Since 47...h5 offers nothing, I think I was planning 47...g5+ 48.hxg5 hxg5 49.Kxg5 Bxe4, but it is a tablebase draw.

47...g5+!? 48.hxg5 hxg5+ 49.Kf5

49.Kxg5 Ke5 wins for Black, according to Komodo11.01, but Stockfish12 still rates the position as drawn. A likely continuation is 50.Kg4 Be2+ 51.Kg3 Bxe4, which is a tablebase draw.

49...g4 50.Bf4+ Kc6 51.Ke5 Kb5 52.Kd5 Bc4+ 53.Kd6 Bf7 54.Be3!?

54.Ke5 looks a simpler way to play it.

54...c4 55.Bd2?

This loses trivially. 55.Ke5 seems to draw, although now it is Stockfish12 that reckons Black is winning, while Komodo11.01 'only' gives Black the upper hand. The problem with the engines' evaluations seems to be that they do not understand Black has the wrong bishop for promoting the a4 pawn. After 55...c3 56.Kd4 c2 57.Kd3 Bb3 they reckon best-play continues 58.Kd2 g3 59.e5 Kc4 60.e6 c1=Q+!? 61.Kxc1 Kd3. By now both engines have had Black winning for quite some time, but with never-changing evaluations (+2.45 for Stockfish1; +2.5 for Komodo11.01). This is often a sign that a position is not in fact winning. Indeed after 62.e7 Bf7 63.Bg1 Ke2 (+3.07 for Stockfish12; still +2.5 for Komodo11.01) 64.Bb6 g2 65.Bc5 Kf1 66.Bb6 g1=Q 67.Bxg1 Kxg1 the game is a tablebase draw, although Stockfish12 gives Black's advantage as +2.29 (Komodo11.01 takes a little time, but comes to recognise the draw).

55...g3 56.Be3 g2 57.Ke5 c3 58.Kd4 c2 0-1