PLAYED this afternoon (for the unusual rules of this event, see https://beauchess.blogspot.com/2021/09/coulsdon-daytime-round-2.html).
English Opening
1.c4 e5 2.Nc3 Nc6 3.Nf3 g6!?
Most popular in ChessBase's 2021 Mega database are 3...f5 and 3...Nf6, but the text is not far behind. However there is a problem with ...g6 in that after ...
4.d4 exd4 5.Nxd4 Bg7 6.Nxc6
... it is hard not to conclude White is better.
6...bxc6 7.g3 Ne7 8.Bg2 0-0 9.0-0 Ba6!?
Grandmasters have tried several moves after 9.0-0, although the text is not one that has found much of a following. The main line in Mega21 goes 9...d6 10.Bg5 Rb8 11.Qd2 with advantage to White, according to Stockfish14 and Komodo12.1.1.
10.Qa4 Qc8 11.Bd2
The engines reckon even stronger is 11.e4 or 11.Rd1.
11...Rd8!?
Ignoring a rule-of-thumb given by first correspondence world champion Cecil Purdy who warned against placing a rook behind an unmoved pawn even if you intend moving the pawn.
12.Rfe1 Rb8 13.Rad1
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| Can Black safely capture the b pawn? |
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Yes! Or at least the engines reckon so. I rejected 13...Rxb2!? because of the forking reply 14.Qa3, but the engines continue 14...Rxd2 15.Rxd2 Bxc4, the point being 15.Qxe7?? loses to 15...Bxc3. So after 15...Bxc4 Black has two pawns (at least temporarily) and the bishop-pair for the exchange, although the engines still prefer White.
13...Nf5 14.Bc1!?
Rather than this passive retreat, the engines like 14.b3, although the white queen does look a little awkwardly placed.
After the text there comes a long semi-forced sequence ...
14...Nd6 15.c5 Nc4 16.Qc2 Qb7 17.b3 Qb4 18.Ne4 Na3 19.Qd2 Qxd2 20.Rxd2 Nb5 21.Bb2 Bxb2 22.Rxb2
... at the end of which AD offered a draw (in my time).
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| Position after 22.Rxb2 - who stands better? |
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White has the better pawn-structure, but the white rooks are a little uncoordinated in the short term. The engines give White a slight edge.
22...f5!?
22...f5!?
The engines prefer 22...d5 23.cxd6 cxd6, but I felt the resulting hanging pawns would make it easy for White to come up with a plan, and anyway I hoped the c5 pawn might prove vulnerable.
23.Ng5 h6 24.Nf3 Re8 25.e3 Nc3 26.Bf1?!
The black bishop might look impressive on the a6-f1 diagonal, but it is not threatening anything and has little flexibility. After ...
26...Bxf1 27.Kxf1
... Black has equalised, according to the engines.
27...Rb5 28.b4 a5 29.a3 Ne4 30.Rd1 Re7 31.Nd4 Rb8 32.Rb3 axb4 33.axb4 Ra8 34.Rb2 Nc3 35.Rdd2 Ree8 36.Kg2 Rab8 37.Rb3 Nd5 38.b5 cxb5 39.Rxb5 c6 40.Rxb8 Rxb8
The exchange of a pair of rooks means the game has definitely reached an ending, and it is dead-equal, according to the engines.
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| The endgame starts |
Activity with 43.Ra7 looks natural. It may be AD was (unnecessarily) worried about threats to his f pawn.
43...Ne4 44.Ke2
Perhaps 44.g4!? is better, getting rid of the e4 outpost after 44...Ng5+ 45.Kf4 fxg4 46.Kxg4, although then White has three pawn-islands against Black's two.
44...Ra8 45.f3
The alternative way to evict the black knight from its outpost.
45...Ng5 46.h4 Ne6 47.Nxe6 dxe6
The Black d pawn at last moves (see note to 11...Rd8!?).
The position remains equal, as also would be the case after 47...Kxe6 48.Rd2 d5 49.cxd6 Rd8, according to the engines.
48.f4 Kf6 49.Kf3!?
Perhaps 49.Kd3, staying closer to the c5 pawn, is slightly better.
49...Ra5
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| White to play and draw |
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50.Rc3?!
Quite a few moves maintain the balance, according to the engines, but this may not be one of them. Komodo12.1.1's top choice is 50.Ke2, and if 50...e5 then 51.Rd2! Rxc5 52.Rd6+ Kf7 53.fxe5 with what the engines agree is dead-equality. Stockfish14 gives 50.g4 g5 51.hxg5 hxg5 52.gxf5 exf5 53.fxg5+ Kxg5 54.Rd2!? Rxc5 55.Rd6, which is a tablebase draw. Note that in both lines White sacs a pawn to activate his rook, a not uncommon theme in rook-and-pawn endings.
50...e5 51.e4?
This is Komodo12.1.1's top choice for a while, but can hardly be best.
After 51.fxe5+ Kxe5 the engines agree White should play 52.h5!? g5 53.g4 fxg4+ and now either 54.Kxg4 or 54.Kg3!?, in each case giving Black a slight edge.
51...fxe4+ 52.Kxe4 Ra4+ 53.Ke3 exf4+ 54.gxf4 Kf5 55.Rd3
The white rook activates, but it is too late.
55...Rxf4 56.Rd6 Re4+ 57.Kf3 Re6
Black is a pawn up, and there seems no way for White to save the c5 pawn.
The game finished:
58.Rd8 Re5 59.Rf8+ Ke6 60.Rh8 h5 61.Re8+ Kf6 62.Rf8+ Kg7 63.Rd8 Rxc5 64.Kf4 Rc4+ 65.Kg5? Rg4#
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