Scotch 4. Nxd4 Bc5 5. Nxc6

Any thoughts on this opening?

I put this in the Chess Openings category since I'm mainly curious about the opening moves.

1. What's the reason 5...Qf6 is the "theory" move instead of 5...dxc6 or 5...bxc6?

2. What are general ideas after 6. Qf3? How do you evaluate the position?

3. How do you evaluate Qxf3 on moves 6, 7, or 8? It seems that white would be fine advancing the e and front f pawns. I figured I had better chances fighting back if I kept my queen, and Qxf6 would speed my development with Nxf6.

4. Do you recommend 6... bxc6 or 6... dxc6? I liked capturing toward the center, but 6... dxc6 opens up my bishop.

5. Is advancing the f pawn appropriate in this position?

Thanks in advance for any responses.

EDIT: That should be a "??" on 21. Bb5, not 21... Be4.

The reason behind 5...Qf6 instead of dxc6 or bxc6 is to keep an active position. An active position is what gives Black compensation for his structural defects.

The idea behind 6. Qf3 is to defend the f pawn in a manner that denies Black activity. Before 6. Qf3 became popular the mainline was 6. Qd2 after which Black could play dxc6 and develop quickly in lines like 6. Qd2 dxc6 7. Nc3 Bd4 8. Bc4 Be6 9. Bxe6 fxe6 10. Nd1 O-O-O 11. Qg5 Qf7. 6. Qf3 does not block in White's bishop, so Black cannot afford to let his pawn structure fall apart. 6. Qf3 dxc6 7. Bc4 Qxf3 8. gxf3 Ne7 is playable, but 7...bxc6 is the mainline.

After 7. Qxf3 White's pawn structure is not really better and the knight on c3 does not have a very bright future.

Thanks aggressivesociopath.

What's the reason to wait to play Qxf3 instead of on move 6? Is playing Qg6 not the best? Is Qxf3 still worth playing when the queen is defended by Nd2 or Be2? (On the chess.com Game Explorer, gxf3 is still the usual recapture even in those circumstances.)

I personally don't trust Qxf3 due to the line 6. Qf3 bxc6 7. Nd2 Qxf3 8. gxf3 Ne7 9. Nb3 Bb6 10. c4 c5 and the bishop winds up out of play and the f4 square subsequently unexploitable 10. d6 c5 and White will regain the pawn and Black's pawn structure is rather poor. I would only play Qxf3 when White's move order has ruled out this possibility, but then again the line is still played by grandmasters and Black can deviate with 8...d5 with an active game.

I don't see the point in 7. Be2 Qxf3 8. gxf3, the bishop does nothing here.

6...Qxf3 7. gxf3 bxc6 8. Be3 Bxe3 9. fxe3 when Black's only active piece has been traded off, the breaks d5 and f5 repair White's pawn structure and the f4 square is unavailable.