Gambit Defense and the "Permanent" Sacrifice

I was recently shuffling pieces around on a pocket set and came across something interesting. I was trying to find advantages achieved through the Nimzovich Defense (1. e4 Nc6) that are not transpositions into other defenses. I found this line to be the most compelling. It arose from White converting to the Vienna Game (1. e4 2. Nc3), an opening I despise playing against as Black.

Here is my line: 1. e4 Nc6 2. Nc3 d5?!

White's most accurate continuation is Nxd5, leading to a "permanent" sacrifice, a sacrifice in which material re-compensation is not forced. 

What happens after 5. Nd2, 6. d3, and fianchettoing the king's bishop? White seems to be just up a pawn with a safe king, good central control, and lots of ways to play.

When I was trying to do the exact same thing you're doing (coming up with things to do with the Nimzovich that didn't happen with other openings) a few years ago, the best I could come up with for 2. Nc3 was 2. ... e6, followed by d5, though that can also be gotten through the French...

I never said the gambit was "good", but I wanted to see what could be achieved through it. 

And by forcing white to fianchetto, the game becomes a closed one for white, which usually defies the point of 1. e4, whilst black has a relatively open game. And, as I said, doubled pawns can be disadvantageous in the endgame.

Any other thoughts?

Honestly I think black has very little compensation for the pawn. You think putting the bishop on b4 trying to double white's pawns is compensation? It's done in the nimzo indian but it costs nothing. The only good thing for black is that since he quickly moved a center pawn white has less chances for the initiative, but his extra pawn is well worth that.

White has the pawn and the compensation.  While this is a slight exaggeration in this position, it was still really fun to say.

I never said it was "compensation". And you can't use the Nimso indian against 1.e4. Besides, the Benko Gambit never gets immediate material compensation for its sacrificed pawn and it's perfectly sound. Now, I never said this was great or even good, but I still think there are advantages to it.

I think 3.exd5 is better white should beable to hold the pawn, or  get ahead in development.

and in the line you posted, why not 9.Nxe5 seems like white has pretty strong advantage at this point.

Good point. As black, I would reply with BxNc3 10. dxBc3 Nxe4 11. QxQ RxQ 12. R-e1 Nd6 13. N-f3 f6. The material inequity is the same as before, but black's position (in my opinion) is just a bit better than it would be otherwise. White's bishop may be able to develop, but black gets just one small advantage in the endgame that it would otherwise not have. With the f-7 square clear to move on (*white has no way of attacking white-square diagonals), black saves himself a tempo in the case that his king needs to centralize in the endgame. Check for yourself: with f7 in place, Black needs to go from g8-f8-e7, one of the center files (*We are assuming king vs. king endgame). With the pawn on f6, it is from g8-f7-e6, one square ahead. That may seem small, but it can make all the necessary difference.

I think you over looked 12.Nxc6 and white is still up two pawns

But in the benko black actually has compensation! The position after the gambit is like a normal black position except with d pawn gone giving black the d file (though he could still be dominated by white's center pawns) and quicker development than usual. It's hard to attack black here, but then again black doesn't have the initiative either! There are no advantages to it whatsoever because there is no way black can expect an attack in that position so he's basically just down a center pawn.

And why are you afraid of the Vienna? Black has no real problems after 2...Nf6 or even 2...Nc6. Against the 3 f4 line just play 3...d5 and if you feel you need to look into just a few more moves and you're fine as far as the theory goes. It's that easy.

ugh...ugly

2...d5?

White is now almost winning.

But a position one pawn down without compensation is lost.

If you want to propose a sacrifice, you need to show serious compensation, otherwise you're just proposing a blunder.

This is the WORST gambit defence i have ever seen. I HATE people that claim they have a new system that ROCKS or WORKS but it DOESNT. even worse, they TRY to compare it to TOP LEVEL gambits that DO WORK.

In 2 moves, black has just lost a pawn with no compensation. The Benk Gambit, black lost a pawn but HAS compensation.

just to quote "Opening novelties of such power are best kept secret, probably in a dark, damp and musty basement." 

Black gains like one tempo here and of course as black you're down a tempo anyway! Generally you need to gain 3 tempi to truly conisder the gambit good. One extra tempo just makes black equal but with one less pawn.

Except here he's lost an important central pawn that would otherwise help control vital central squares. Killabeez is right above, White has the pawn AND the compensation.

That's probably the most helpful criticism I've seen yet. Thanks, Elubas.