As a Svesnikvov player (rated ~1800) the following idea was shown to me recently:
[Title "11. ..Qg5!?"] [StartFlipped "1"] [fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"] 1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 e5 6.Ndb5 d6 7.Bg5 a6 8.Na3 b5 9.Bxf6 gxf6 10.Nd5 f5 11.Bd3 Qg5!?
It seems quite interesting. At least 12. Nc7+ grabbing the rook leads to a nice game for Black. However White is not forced to do that.
- g3 is the obvious alternative, when 12. ..Rb8 seems playable. Maybe one can sac the rook even here?
However 12. ef is the computer‘s choice. The tactical point is that 12. ..Qxg2 13. Nf6+ K somewhere Be4 is just horrible for Black – and in many other variations he has problems getting the pawn back. After guarding the fork with Kd8 (or sth. else? Maybe saving the rook ist not necessary here?) White can castle. And whenever Black tries to get his pawn Back, White plays f4 with a great game. The best I found here was some line where Black got an ending with a horrible Bishop and worse pawn structure – also not very satisfying.
I‘d like to apply such a move against stronger opponents (rated 2000+, even 2200+ [in a Swiss tournament I could face such opponents]), where my "normal" winning or even drawing chances are not that great. So it is not that big of a deal if I get a slightly worse game, but I want to have great fighting chances – and the advantage that I have pre-analysed the position at home. I am also willing to give away "some" material (the f5 pawn, the a8 rook) for a nice attack. I just do not want to play the line the computer recommends after 12. ef – that‘s definitely not a position I can hold against a stronger opponent.
So my question is: Do you have any experience playing this line? Are many players aware of 12. ef or find that move on the board? Is there a more fighting continuation (which may be objectively worse, but where White has to play very precise)? If White does not grab the rook right away with 12. Nc7+, do I really have to protect it next move? For example, after 12. g3, does Black have (crazy?) attacking chances, if he gives up his rook?
I do not want to discuss the concept of playing an objectively worse move against a stronger opponent just to get some chances, if he fails to find the best moves. Both "Forget about 11. ..Qg5, just spend your time on analysing 11. ..Be6 and try to beat your opponents there" or "play the board, not the player!" may (or may not) be reasonable suggestions, but they are of no interest here.