Analysis of a dangerous line against the ...Nf5 advance caro?

This was from a tournament game I played last night. I've felt relatively confident in my Caro-Kann, but this line is really causing me a headache. See comments in diagram.

Opponent (~2040) vs Me (~2090)

OPENING MOVES

THE "CRITICAL DECISION"

So, what of this line? It seems that the Nd2-Nb3 line, intending to always meet ...Be7 with g4, is very scary for black. My opponent was only rated 2040 and had begun this tournament .5/6, but seemed to effortlessly get a position that was not only good, but easy to play. Any suggestions for improvements in the opening for black?

I think you played it well until 18... Nb6?. Your Nd7 guards c5 and can be relocated to f8, if necessary. On b6, he does nothing.

Much better looks 18... Bd6 instead, followed by Qf8/e7/c7 (depending on white's move) and activation of your QR. You have play against f4 and the better minor pieces.

I see no threat of a white pawn storm; h5/g6 can be met with Rf6 and h5/h6 can be ignored. White has no time to add piece support for the attack, your play against f4 is faster.

White has the option to exchange on f5, followed by a mass exchange on the e-file, so the position looks pretty equal to me.

One move later, 19... Bd6 was still playable but 19... g6? pretty much threw the game away.

Thanks! That may be true. Nonetheless, white has other dangerous options like 17. Rxe6 that would make me nervous to go into this line again. I wonder what the final assessment of the exchange sac would be, but practice has favored white, I believe.

I think I subconsciously understood that 18...Nb6 was bad, but it seemed to be my only try for activity, and with my opponent being lower-rated, I hoped he might misjudge something and allow me way more counterplay than I deserved. If I park the knight on f8, which might objectively see better, I don't see anything black can do besides hope he doesn't get beaten. I wasn't sure that my "play against f4" would ever really amount to anything, compared to the pressure on e6

Hmm, that's interesting, I wasn't familiar with ...Be4 there. I guess that's an option in the Nd2-Nb3 and Bd2 line...still doesn't look easy for black.

Glad to hear it! That's part of why I put so many annotations in the diagrams

What about 1. e4 c6 2. d4 d5 3. e5 Bf5 4. Nf3 e6 5. Be2 Nd7 instead? Looking to play c5! the break.

This is the critical line (after 21...Nd6):

Black has decent compensation for the pawn in the form of the better minor piece, but analysis is required.

what is black's alternative to 7..Bg6

If White avoids trading off his Good Bishop for Black's Bad Bishop on f5, usually with Bd3 Bxd3, Qxd3, then Black is stuck with where to post his KB, initially placed on e7, who works well at f5.

Because White made a relatively passive move with Be2, Black can afford to lose the tempo to play Bg6 then Nf5.  At f5, the N is much better posted than if you left the B on f5 and moved the N to g6 - or over toward the Q-side to get Black's Good Bishop at f8 room to move.

I can't go into any detail because I just happen to have a very similar position in a 3 day/move game, where I recently made the ...Bg6 and ...Nf5 moves in the Caro and don't want to expose my intentions: loose lips sink ships.

In your critical decision variation line with 13...Nxf6 instead of 14...Ne4 after g5, I am thinking you could you try 14...Ng8? I am thinking that you will be able to get your knight to either f5 or g6 to defend the bishop if necessary. After something like 15.Bh5 (15.Bd3 Ne7  [the f5 break looks dangerous after something like 15...Bxd3 16.cxd3 Ne7 17.Qh5+ Ng6 18.f5?! exf5] )16. Qg4 Bxd3 17.cxd3 Nf5