9

I was looking at analysis on one of my games and found this variation against a Yugoslav attempt against the Sicilian Dragon which Stockfish 12 instantly says is +2.6 for white:

[FEN ""]
[Result "1-0"]
[ECO "B50"]
[Opening "Sicilian Defense"]
[Termination "Normal"]

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nc6 5. Nc3 g6 6. Be3 Bg7 7. f3 e5 1-0

Once black plays e5 on move 7, Stockfish changes its +0.8 evaluation to +2.6, but if I play the game out with best moves from both sides using Stockfish I kind of don't see why it is so good. White wins by a lot, but I don't really understand why. Could somebody please help me understand why this move is so bad for black considering it doesn't seem to lose material if black plays correctly? And moreover, is this something I can punish if I see it again or is it just some weird super deep engine idea that a (non-GM) human couldn't really use?

1
  • A very interesting question! Thanks for asking it! :) Commented Jan 7, 2021 at 23:38

2 Answers 2

12

This move creates several weaknesses, at f6, d5, and d6, and restricts the movement of the Bg7.

The outpost weakness is usually shown by the game https://www.chessgames.com/perl/chessgame?gid=1257953.

The d6 weakness is basically using all you pieces to attack the pawn and, once all of black's pieces on defending it, to shift the attack to another point and, hopefully, the black pieces can't respond quickly enough.

The f6 weakness is harder, but basically pushing a pawn to f5 forces black to capture and expose f7 to attack.

The restricted movement of the bishop is exploited in the endgame when the bishop can't react quickly enough to both protect d6 and the dark square weaknesses.

12

Besides Mike Jones' correct positional explanation, Black is also losing material at once after the simple 8.Ndb5.

White attacks the d6 pawn, whose capture would also deprive Black of castling rights. 9.Nd5 followed by a fork on c7 is an even bigger threat ensuring that there is no defense:

8...Bf8 9.Nd5 Rb8 (what else ?) 10.Nbc7 Kd7 is awful, when the cleanest finish is probably 11.g3 Nge7 12.Bh3 f5 13.Bg5 h6 14.ef5 hg5 15.fg6 Nf5 16.Bf5#

8...Ke7 9.Nd5

8...Nd4 9.Nd4 ed4 10.Bd4 wins a healthy central pawn and keeps White's positional pluses.

8...Nge7 9.Nd6 Kf8 might be the lesser evil for Black, but your engine's evaluation is totally justified here.

8...Qa5 9.Bd2 doesn't solve anything.

Black is dead lost.

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