The Giuoco Piano after 4.c3 Nf6 5. d4 exd4 6. e5

Question

[FEN ""]    
  1. e4             e5            
  2. Nf3            Nc6            
  3. Bc4            Bc5           
  4. c3             Nf6          
  5. d4             exd4
  6. e5

I've faced this line as black a couple of times. Unfortunately all I know about this line comes from Burgess's The Mammoth Book of Chess, where he treats this in a couple of sentences: he says it can be highly effective at club level, and that black needs to find the counter-thrust 6...d5 to get a satisfactory position.

My question is, what does black do after 6...d5 7. Bb3? One of my opponents confidently played that against me. I was out of book, played 7...Ng4, and he developed a strong initiative. Now that I check the position with an engine, the engine suggests 7...Ne4 8.cxd4 Bb4+ 9.Bd2 Nxd2 10.Nbxd2 Bg4 and evaluates as a very small advantage to black. However engine analysis is just a bunch of lines, not very human-comprehensible.

Can anyone familiar with this line give me some pointers on how to treat this position?

Answer 1

(Answering my own question since I got some help from an expert)

Bb3 is a weak move, since the game will soon be focused around the d4-square. White should have played 7. Bb5, pinning the knight. Playing Bb3 instead yields an inferior version of what happens next.

e4 is the best post for the knight - it's a central square, and it's defended as well. Now white has to play 8. cxd4 or he'll be down a pawn. Black responds with Bb4+. The aim of this move is to force a minor piece to d2, which interferes with the queen defending d4. After 8...Bb4+ 9. Bd2 Nxd2 10. Nbxd2, black plays Bg4 pinning the knight and making it very difficult for white to defend the d4-pawn. If white plays 9. Nbd2 instead black can just continue with Bg4 and leave the c1-bishop to stew.

Now white's position starts to get unpleasant. In addition to Nxd4, black threatens 11...Bxf3, ruining white's pawn structure (11. a3? Bxf3 12. Qxf3? Bxd2+ 13. Kxd2 Nxd4 wins a pawn since 14. Qxd5?? Nxb3+ wins the queen). White has to play 11. Ba4, which shows why 7. Bb5 occupying the diagonal sooner was the correct move. Black's position is still preferable: white's knights are pinned, and after 11...O-O 12. Bxc6 (forced) bxc6, black is ready to play ...c5 contesting the center. In the final analysis position below, black has more space, the initiative, and the bishop pair.

[FEN ""] 
     1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d4 exd4 6. e5 d5 7. Bb3?! Ne4 8. cxd4 Bb4+ 9. Bd2 (9. Nbd2? Bg4) Nxd2 10. Nbxd2 Bg4 11. Ba4 (11. a3? Bxf3 12. gxf3 Ba5) O-O 12. Bxc6 bxc6 13. O-O c5

As to what happens after 7. Bb5 ... that's another question entirely =)

Answer 2

[FEN ""] 
     1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d4 exd4 6. e5 d5 7. Bb5 Ne4 8. cxd4 (8. Nxd4 {Is the Scotch Gambit.  Considered good for white in most lines.}) Bb4+ 9. Nbd2 Bg4 10. a3 Bxf3 11. Bxc6+ bxc6 12. Qxf3 Nxd2 13. Bxd2 Bxd2+ 14. Kxd2 {white has good pressure down c-file}

Both are good lines, however too much to explain here. But the doubled pawns are compensation for the two bishops, if black can keep them, and the weak dark squares are a nightmare for black.