Masters have learned to exploit certain pawn moves with a quick reflex.
Jiri Vesely White
Karel Opocensky Black
Jablonec 1962
Caro-Kann Defense B16
1 e4 c6 2 d4 d5 3 ♘c3 dxe4 4 ♘xe4 ♘f6 5 ♘xf6+ gxf6 6 ♘f3 ♗f5 7 ♗c4 ♘d7 8 0-0 e6 9 ♗b3 b5?
Black tries to secure d5 for his knight (...♘b6-d5) by anticipating c2-c4. But he gives White a target, either at c6 or b5.
10 a4!
The proper knee-jerk response. A c6 target appears after 10...bxa4 11 ♗xa4.
10...♘b6?
Despite appearances, this fatally weakens Black’s control of d5.
Better was 10...b4 with a slight inferiority after, say, 11 ♗f4 ♘b6 12 ♘h4 ♗g6 13 ♕f3.
White also gets the upper hand from 10...a6 11 axb5! axb5 12 ♖xa8 ♕xa8 13 ♘h4 ♗g6 14 ♕e2. Or 11...cxb5 12 d5!.
11 axb5 cxb5 12 ♕e2!
Now 12...a6 13 ♖xa6! (13...♖xa6 14 ♕xb5+).
12...♕d7 13 d5!
This blasts open the d-file, e.g. 13...♘xd5 14 ♖d1 with a threat of 15 ♗xd5. For example, 14...♗e7 15 c4! bxc4? 16 ♗a4 or 14...0-0-0 15 ♗e3 and ♖xa7. Or 13...e5? 14 ♘xe5!.
13...♘c4 14 ♘d4! ♕xd5
Another loss is 14...♗e7 15 ♘xb5! (15...♕xb5 16 ♗a4).
15 ♘xb5! ♖c8 16 ♖d1 ♕e4 17 ♗a4! resigns.
The neat end would be 17...♕xe2 18 ♘c7+ ♔e7 19 ♖d7 mate.
Larisa Dergileva White
Heike Vogel Black
Germany 2004
1 e4 c6 2 d4 d5 3 ♘c3 dxe4 4 ♘xe4 ♘f6 5 ♘xf6+ gxf6 6 ♗c4 ♗f5 7 ♘f3 e6 8 0-0 ♗d6 9 ♘h4 ♗e4? 10 ♕h5! ♗d5 11 ♗xd5 cxd5 12 ♖e1 ♕d7 (12...0-0 13 ♗h6 is lost) 13 ♘f5 ♗f8 14 ♗h6 ♖g8 15 ♗xf8 ♖g5 16 ♕xh7 ♔xf8 and now 17 ♕h8+ or 17 ♘h6 win.
Question 29: What was White’s threat after 13 ♘f5 ?