A tactic on the Chekhover variation of the Sicilian? Recently I found the game Tal vs. Byrne (1976), that opens with Chekhover Variation of the Sicilian Defense. What got my attention in this variation was move 7, for, just like Tal did, every engine says that the best move is 7. Nc3, but for some reason I like how 7. Ng5 looks:

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1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Qxd4 Nc6 5. Bb5 Bd7 6. Bxc6 Bxc6 7. Ng5!? (7. Ng5 e5 8. Qc4 Qd7)


Stockfish 6 says it is slightly better for black (-0.8 at depth=22 to be precise), but the main idea is simply to explore the weakness of the f7 pawn. The main line I was thinking was 7... e5 8. Qc4, the natural urge to punish the white queen at the center creates the threat of mate on f7, so black is somewhat obligated to lift the queen to the 7th rank. Anyway, if this "trick" fails, for example after 8... Qd7, there is no immediate advantage for white, and it seems that the only difference from Tal's 1976 variation is that here white is behind in development (and ready to be punished!).

I couldn't find any game with the move 7. Ng5 in chessgames.com, but I still think that it is a natural looking move that seems to have a possible tactic behind it, even if I wasn't able to find. So my question is:


  Is 7. Ng5 really only a bad move? The downside is that obvious? Or there is a possible tactic behind it? (besides the threat of mate on f7 after 7... e5 8. Qc4)
Strategically the knight is misplaced on g5.  When black plays e5 in the Sicilian, the ideas revolve around white trying to control the d5 square, and black trying to play d6-d5.  Simply put, if black can play d5 damaging his position (i.e. sometimes if the king is still in the center d5 opens up the black king) black will have a clear advantage due to the central pawn majority.  

In order to control the d5 square, white usually plays Nc3 and Bg5.  Bg5 is important because it will either pin black's knight to the queen or allow white to trade off black's knight that controls d5.  With the white knight on g5, black will eventually gain a tempo by playing h6 which will also prevent access to g5 by the dark square bishop.

Additionally, with the queen out of the way on d7, black can quickly play Ra8-d8 in order to take better control of the d file and help support the eventual d5 push.  All of this would be pretty comfortable for black anyways, but in the Chekhover, black also has the bishop pair which will benefit from the opening of the center when black plays d5.  

Long story short, white is ceding a fairly large positional edge to black in exchange for some very short term tricks.  That's not to say that white is losing, but after Ng5, black can easily claim equality straight out of the opening, and black has very good prospects to consolidate an advantage.