breizatao wrote on 11/27/09 at 13:12:59:

Why allow the pawn structure to be corrupted in this way? O.Renet recommended 15.Kh1 a4 16.Rg1 etc. with advantage. This looks pretty good for White. Black has no time to take the piece.
This variation has been debated heavily before on this Forum .

So I've been reading Mihail Marin's Beating the Open Games, with special interest in his treatment of the King's Gambit section. The deepest main line he gives a serious look at involves White's 10. Qd2!? as in the following:

1. e4 e5 2. f4 Bc5 3. Nf3 d6 4. Nc3 Nf6 5. Bc4 Nc6 6. d3 Bg4 7. Na4 O-O 8. Nxc5 dxc5 9. O-O Qd6 10. Qd2 

Here he takes quite some effort in explaining how potent this move is and what black has to look out for. Ultimately he gives this as the best continuation:


10...Bxf3 11. gxf3 exf4 12. Qxf4 Ne5 13. Bb3 b5 14. Be3 Qe7 

Threatening Nfd7 in his words. Now I thought about this and started some deep analysis with Rybka on my Quadcore computer. Rybka suggests simply renewing the pin with 15. Qg5! and now black is in a bit of a pickle here. As far as I can tell with Rybka, EVERY try by black other than 15...h6 loses. So after 15...h6 16. Qg2, it just seems to me white is doing considerably better here than black. White has created a weakness in black's castled position by force, and got to relocate the queen to the excellent g2 square. I can see white simply playing Kh1 followed by Rg1. He's got the bishop pair, the better center, and an open g-file lane of attack against the already weakened fortress around black's king. I would NOT want to play this as black, and even less so in a CC game. Indeed the CC results I've found for anything coming close to this line show black losing badly.

So to recap:

1. e4 e5 2. f4 Bc5 3. Nf3 d6 4. Nc3 Nf6 5. Bc4 Nc6 6. d3 Bg4 7. Na4 O-O 8. Nxc5 dxc5 9. O-O Qd6 10. Qd2 Bxf3 11. gxf3 exf4 12. Qxf4 Ne5 13. Bb3 b5 14. Be3 Qe7 15. Qg5 h6 16. Qg2 

And white's advantage is close to +0.50 already according to Rybka, but I don't even have to see the score to notice the position looks heavily in white's favor. To me, it puts the whole 6...Bg4 line into jeopardy.