Modern/Pirc
1.Nc3 g6 2.e4 Bg7 3.d4 c6 4.f4 d6 5.Nf3 Nf6 6.Be2 0-0 7.0-0
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| With both sides castling early, how would you assess the position? |
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White has more space and a slight lead in development, which together give the upper hand, according to Stockfish17.1 and Dragon1.
7...a5!?
This is Stockfish17.1's top choice, for a while, and is anyway preferred over the much more popular 7...b5, which the engines agree is well-met by 8.e5. Dragon1 also prefers the text over 7...b5, but to a lesser degree, and eventually both engines settle on 7...Nbd7!? as best.
8.a4 Qb6 9.Kh1 Na6 10.Ra3!? Bd7 11.Rb3 Qc7 12.Be3 Ng4 13.Bf1 Nb4 14.Qd2 d5
The engines dislike this, preferring 14...Rad8 or 14...Nf6.
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| How should White proceed? |
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15.h3
The engines much prefer 15.e5.
15...dxe4!
This equalises, according to the engines.
16.Nxe4 Nf6 17.Nc5 Bc8
The engines give 17...Bf5!, the point being 18.g4 can be met by 18...Ne4 (not 18...Bxc2?? 19.Rxb4 etc) 19.Nxe4 Bxe4, when they reckon Black is at least slightly better. White should probably play 18.c3, when 18...b6 19.cxb4 bxc5 seems equal.
18.c3 Nbd5 19.f5!?
White gets reasonable compensation for this pawn sac, but I probably should have gone for my other main thought of 19.c4!?, and after 19...Nb4, best may be 20.Ne3.
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| How should Black respond? |
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19...b6!?
This zwischenzug is Black's best chance for an edge.
20.Bh2 Qd8 21.Nd3
21.fxg6!? is probably asking too much of the position after 21...bxc5, eg 22.gxh7+ (the engines reckon this is is better than taking on f7) Nxh7 (22...Kh8!?) 23.dxc5 Bf5!? 24.Ne5 Be4!?, with a complicated position that the engines reckon favours Black.
21...Bxf5 22.Nfe5 Ne4!? 23.Qc1 Qc8?!
The engines suggest 23...Rc8 or 23...f6, claiming a slight edge for Black.
24.c4 Nb4 25.Nxb4 axb4 26.g4!? Be6 27.Bf3 Bxe5!?
This looks risky, but Dragon1 reckons it is best. Stockfish17.1 also likes the text, but reckons 27...f6 is as good.
28.Bxe5 Nd6 29.Qh6 f6 30.Bxd6 exd6 31.d5!?
31.Rxb4 regains the pawn and gives complete equality, according to the engines.
31...cxd5 32.cxd5?
Capturing on b4 is best.
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| Black to play and win |
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32...Bf7?
Missing 32...Qc4!, forking the white rooks.
33.Rfc1 Qd7 34.Rxb4 Ra5
There seems nothing wrong with 34...Rxa4.
35.Qd2 Rc8?!
Capturing on a4 is still playable, and is better than the text.
36.Rxc8+
Possibly stronger is 36.Rc6!?, with a slight edge, according to Dragon1, although Stockfish17.1 reckons the position is equal.
36...Qxc8 37.Rxb6 Rxa4
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| How would you assess this late-middlegame? |
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The engines reckon the position is completely equal.
38.Rc6
Not 38.Rxd6? Ra1+, eg 39.Kg2 Qc5 40.Rd8+ Kg7 41.Qf2 Qc7, and White's rook drops, or 39.Bd1 Qb8! 40.Rxf6 Qb3 etc.
38...Qb8 39.Qc3?
Probably best is 39.Kg2, with equality, according to the engines.
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| Black to play and win |
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39...Kg7?
Missing 39...Ra1+, followed by 40...Qa7, eg 40.Kg2 Qa7 41.Kg3 Qg1+ 42.Bg2 Re1 etc.
40.g5 Qd8?
Black has to play 40...Rf4, according to the engines, and after 41.gxf6+ probably has to continue with 41...Kh6!?, as 41...Rxf6 42.b4 gives White a dangerous queenside initiative.
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| White to play and win |
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41.gxf6+
This wins a pawn, but not the game, whereas 41.b4! wins comfortably, according to the engines, as Black cannot cope with pressure against f6 and d6 as well as the advancing passed pawn.
41...Qxf6 42.Rxd6 Qd4!
There is no win after this.
43.Kg2 Rb4 44.Kg3 Rc4 45.Qxd4 Rxd4 46.Rd7 Kf6 47.b3 h5 48.h4 Rb4 49.Bd1 Rd4
EMP offered a draw in my time.
50.Bc2 Rxd5!?
The engines do not like this because they do not understand the coming bishop-and-pawn ending. Stockfish17.1 reckons the move gives White the upper hand, while Dragon1 reckons White's advantage after the text is worth more than a rook, but they are both wrong.
51.Rxd5 Bxd5 52.b4
This allows complete equality, but so does 52.Kf4 as Black has 52...Bxb3!, which the Syzygy endgame tablebase confirms is a draw (White's bishop is on the wrong colour complex for promoting an h pawn).
52...g5 53.b5 Bb7 54.Bd1 Kg6 55.Bf3 gxh4+ 56.Kf2 Bc8 57.b6 Kg5 58.Kg2 h3+ 59.Kh2 h4 60.Bd5
EMP offered a draw.
60...Kf5 61.Bc6 Ke5 62.Bd7 Bb7 63.Bxh3 Kd6 64.Bg2 ½–½
The note to move 50 is something I have noticed as well. Engine assessments of positions that could reach the drawn Bishop and wrong Rook's pawn ending are unreliable as they seem to come up with phantom advantages. Presumably if the engine had access to a relevant tablebase it could get it right.
ReplyDeleteRdC
It's an interesting one. You would think there would be a way to quantify the concept in computerspeak, but perhaps there isn't.
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