Disturbing my plans.

Let my apologise first for my long absence - I was quite busy professionaly and had a week's holiday in Italy.

In my quest to demonstrate a theoretical equal line for white in the Teichman defense, I am looking at the "dubious" 11.Bg5 after 1.d4 d5 2.e4 dxe4 3.Nc4 Nf6 4.f3 exf3 5.Nxf3 Bg4 6.h3 Bh5 7.g4 Bg6 8.Ne5 e6 9.Bg2 c6 10.h4 Bb4

In earlier blogs, I proved that the attacker is better after the natural 11...Nbd7 and has equal chances ( even if white had to trade 6!!! pawns for a piece ) after the challenging 11...Qa5.

Let's look today at 11...h6 (diagram), another black try to disrupt white's plans.

It seems to me that this weakens black's position in two ways :
1. a timely exchange of the bishop on g6 yields a double pawn on g6 and an isolani on e6
2. white may consider sacrifing his bishop on h6 when black castles into it.

Unfortunately, my silicon assistant does not always see things the way I see them... As an example, Stockfish first thinks 12.Nxg6 is roughly equal, but, when thinking deeper, prefers 12.Bf4, then switches back to 12.Nxg6, then again 12.Bf4. So it is clear Stockfish is confused.

Let's look at both lines.

a/ 12.Nxg6 fxg6 (diagram)
Let's look at three different white lines

...a1/ 13.Bxf6
......a1a/ 13...Qxf6 14.Qd3
.........a1a1/ 14...Bxc3+ 15.bxc3 Nd7 16.g5 (=)
.........a1a2/ 14...00 15.000 (+=)
.........a1a3/ 14...Nd7 15.000 (=)

......a1b/ 13...gxf6 14.Qd3 (+=)

......a1c/ 13...Bxc3 14.bxc3 Qxf6 15.Rb1 (=)

...a2/ 13.Bf4

......a2a/ 13...Bxc3 14.bxc3 (=)
......a2b/ 13...Nd5 14.Bd2 (=+)

......a2c/ 13...00 14.00 (=+)

...a3/ 13.Be3

......a3a/ 13...Bxc3 14.bxc3 (=)

......a3b/ 13...Qd6 14.00 (=+)
......a3c/ 13...Nd5 14.Qd3 (=)
......a3d/ 13...00 14.00 (=)

b/ 12.Bf4 (diagram)

...b1/ 12...Nd5 13.Nxg6 

......b1a/ 13...Bxc3+  14.bxc3 fxg6 15.00 (=)

......b1b/ 13...fxg6  15.00 (=)

...b2/ 12...Be4 13.Bxe4 (=)

...b3/ 12...Bh7 13.g5 (=)
...b4/ 12...Ne4 13.Nxg6 Nxc3 14.bxc3 Bxc3+ 15.Bd2 (=)
...b5/ 12...Nbd7 13.Nxg6 fxg6 14.Qd3 (=)
...b6/ 12...Nfd7 13.Nxg6 fxg6 14.Qd3 (+)
...b7/ 12...Nfd7 13.Nxg6 fxg6 14.Qd3 (+)
...b8/ 12...00 13.00 (=+)

So we see that the challenging 11...h6 is no roadblocker for playing 9.Bg2 c6 10.h4 Bb4 11.Bg5 in  the Teichmann defense. The retreat 12.Bf4 might be a bit shaky after 12...00, but the immeidate 12.Nxg6 fxg6 13.Bxf6 offers white an equal game.