4NCL Division Four, Round Four, Board Five (of six)
Sicilian Bb5(+)
1.e4 c5 2.Nf3 d6 3.Bb5+ Nd7 4.c4!?
The mainline in ChessBase's 2022 Mega database runs 4.0-0 a6 5.Bd3!? Ngf6 6.Re1 e6 7.c3 b5 8.Bc2 c4 9.a4 Bb7 10.d4 cxd3, when Stockfish15 and Komodo13.02 reckon 11.Qxd3 and 11.Bxd3 give rough equality.
4...Nf6 5.Nc3 g6 6.d4 cxd4 7.Nxd4 Bg7 8.0-0 0-0 9.Qe2?!
A novelty, it seems, and probably not a good one. The engines suggest 9.Bxd7!? Bxd7 10.Qd3 with what they reckon is equality.
9...a6?!
Black is at least slightly better after 9...Nc5, according to the engines, eg 10.Rd1 a6 11.Ba4 Nfxe4!
10.Ba4?!
The game is equal, according to the engines, after 10.Bxd7, a capture White commonly makes in 3.Bb5+ Nd7 lines when the light-square bishop is challenged by ...a6.
10...Nc5
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| Can White prevent Black winning a pawn? |
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No.
11.Bc2
11.Rd1 transposes to the note at Black's ninth move, but the engines reckon the text is a little better, albeit still losing a pawn.
11...Nfxe4! 12.Nxe4 Bxd4 13.Rd1 Nxe4?
White gets excellent compensation after this. Not 13...Bh6?? 14.Nxc5, but best, according to the engines, is 13...Ne6 with the upper hand for Black.
14.Rxd4 Nf6
Possibly slightly better is 14...Nc5, but the black kingside looks bare.
15.Bg5
The engines suggest 15.Qd2 or 15.c5!?
15...Qc7
I was more concerned about 15...Qb6, hitting d4 and b2, but the engines reckon White is better, eg 16.Qd2 Qxb2?! 17.Rb1 Qxa2?! 18.Bxf6 exf6 19.Qc3, trapping the black queen. The engines suggest 16...Re8!? but give White at least a slight edge.
16.Bxf6!?
Cashing in the bishop-pair for pressure against d6 and the possibility of having much the better pawn-majority. Stockfish15 prefers 16.h3!? Be6 17.Qd2 Rfe8!? (17...Bxc4? 18.Rc1) 18.Rh4, claiming at least a slight edge for White. Komodo13.02 suggests 16.b3, but reckons the position is equal.
16...exf6 17.Rad1 Rd8 18.b3 Be6 19.Qd2 f5?!
I thought 19...b5!? was more to the point, eg 20.cxb5 axb5 21.Be4 can be met by 21...Ra3 or the engines' 21...Ra6. Instead 20.Be4 Rac8 21.cxb5 axb5 is equal thanks to White's back-rank weakness.
20.Rxd6 Rxd6 21.Qxd6 Qxd6 22.Rxd6 Rc8
Maybe better is 22...b5.
23.Bd3 Kf8 24.Kf1 Ke7 25.Rd4 Rd8?!
NC offered a draw, but, as usual, keeping rooks on is a more likely way to split the points.
26.Rxd8 Kxd8
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| How would you assess this bishop-and-pawn ending? |
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Material is level but White's pawn-majority is clearly better than Black's despite all the white queenside pawns being on light squares. Stockfish15 reckons White is winning, but Komodo13.02 gives White 'only' the upper hand.
27.Ke2 f6!?
The engines are fine with this. I expected something like 27...Kd7 28.Ke3 Kd6 29.Kd4 b6, when White remains better.
28.Ke3 b6 29.Kd4
White gets a passed pawn after 29.c5!?, whether or not Black captures, but the engines are unsure if it is better than the text.
29...Kc7 30.Be2 Kd6 31.Bf3
The engines prefer, for example, 31.g3!?, mainly to stop ...f4.
31...a5
31...a5
White has just a slight edge after 31...f4!?, according to the engines.
32.a3
Again the engines prefer g3, or 32.Bd5 Bd7 33.g3.
32...h6 33.b4 axb4 34.axb4 g5
Best is still ...f4!?, according to the engines.
35.c5+ bxc5+ 36.bxc5+ Kc7 37.Bd5 Bd7 38.g3
At last!
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| How much better is White? |
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I was to find it very difficult to make progress, but Stockfish15 gives White an advantage of +3.29 while the more conservative Komodo13.02 calls it +1.54.
38...Ba4 39.Be6 Bc2 40.Kc4 Bb1 41.Bd5 Bc2 42.Kb5 Bd3+ 43.Kd4 Bc2 44.Kc3 Bb1 45.Kd4 Bc2
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| How should White proceed? |
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46.f4!?
The engines are not keen on this, and even less so on 46.h4!? One line suggested by Stockfish15 runs 46.Bc4 Kc6 47.Be2 Be4 48.Bd1 Kd7, when both engines still reckon White is winning, but seem unable to come up with a way to actually improve White's position.
46...g4?!
This puts another pawn on a light square. The engines reckon White's advantage is identical after both 46...Bd1 47.Be6 Bg4 and 46...gxf4 47.gxf4 Bd1 (about +1.36 in each case), a factor that often indicates an advantage is illusory.
47.Bg2 Bb1
Best, according to the engines, is 47...Ba4 48.Bf1 Be8, but 49.Bd3 is strong, eg 49...Bg6 50.Bc4 Be8 51.Be6 Bg6 52.Kd5 h5 53.Bg8 and the white king invades, or 49...Bd7 50.Kd5 Bc8 51.c6, after which the black bishop cannot move.
48.Bf1 Ba2?!
This loses without much of a fight, but 48...Kc6 49.Bg2+ Kc7 50.Bd5 Bc2 51.Bc4 Kc6 (51...Be4 52.Bd3) 52.Be2 Bb1 (52...Be4 53.Bxg4) 53.Bd1 Ba2 54.Ba4+ Kc7 55.Bc2 Be6 56.Bd3 Kc6 57.Bc4 Bc8 58.Bb3 also forces a breakthrough.
49.Bc4
Now the white king invades and the rest is easy.
The game finished:
49...Bb1 50.Kd5 Be4+ 51.Ke6 Kc6 52.Kxf6 Kxc5 53.Be6 Kd6 54.Bxf5 Bxf5!? 55.Kxf5 h5 56.Kg5 Ke6 57.Kxh5 Kf5 58.Kh4 1-0
Wessex Some Stars won the match 5-1.
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