I agree that it is logical to have one thread for all Bd7-lines. I also agree that the focus is on move order a) for the time being.
MNb wrote on 12/26/07 at 03:15:38:
Have you ever played gambits yourself? I suspect not or you would be more suspicious of 10.a3. At move 4 White's only compensation consists of a lead in development. His first task is to activate all his pieces and his second one to convert this lead into something concrete. The latter usually happens during the transition from opening to middle game. Now at the tenth move White still has two passive pieces: Ra1 and Bc1. Moreover Black has not made any concession yet. Still you want to play a prophylactic move, a move to preserve your bishop? Such logic suits the quieter variations of the Open Sicilian, not the Morra Gambit. My first and probably also my second reaction is that White does not have time for it.
I assume you didn't intend this to be as condescending as it appears. Yes, of course time is important in gambits, and of course 10.a3 is a kind of concession, but so is every White alternative including 10.Bf4 (which gives Black ...e5 with tempo, going into the respectable Classical Morra structure). The entire point of Black's move order is to put White in this "minor zugzwang", and to achieve this Black has himself made the slight concession ...Bd7, which may often turn out not to be the optimal square for the bishop.
In fact, the move a3 (between move 10 and 15) appears in many of those OTB games where, in my view, White has come closest to equalizing. They also involved some of the strongest tournament players who have risked the Morra with White, which is enough reason to take it seriously and prepare for it:
Parma-Eliskases 1962 1/2
Rizzitano-Benkö 1978 1-0
Nemet-Klauser 1993 1-0
Burgess-Stage 1993 1/2?
Mi.Zelic-Pataki 2004 (2) 1-0
Equidistance-Sophistry 2006 1/2 (note especially this endorsement from the strong Equidistance Freechess team)
So the respect shown to an early a3 does not, as you seem to suggest, rest solely on my own gambit experience (I have played the Evans, King's Gambit, Blackmar-Diemer and Benkö Gambit in rated tournament games, but only a game or two with each. Nowadays I have more respect for the value of material.)
Concretely, after
10.a3 Nf6 11.Bg5 Black may well be better off than in the other Bd7 lines, but sticking to my assumption that those lines are dubious for Black, allowing Bg5 still feels wrong to me. However, your line with
10.a3 Qc7 looks interesting and possibly good for Black. If in the end Zelic's Nd5 gives White enough compensation against both 10...Rc8 and 10...b5, I still have MNb's 10...Qc7 to look into.

So while a3 is a move White often plays at some point maybe move 10 is not the right time (and maybe no time is right... we will see).
Returning to the main line
10.Bf4 e5 11.Be3 Nf6 I think we can agree that 12.h3 is a luxury White should try to do without.
In general when White just builds up (like Rd2/Rad1, Rac1 with or wthout a3, etc.) Black must find some way to make progress without falling for tactics on the d-file, or simply dropping the d-pawn. I usually operate with four main plans that are not all mutually exclusive:
1) Try to get in ...Bg4 and ...Nd4. Experienced Whte players either prevent this with h3 or keep the bishop on e3. I don't usually play ...Bg4 unless the Nd4 follow-up is likely to be available, but maybe I should consider it more often since h3 and especially g4 are very committal moves from White.
2) Playing ..Be6 which invites Bxe6 fxe6. In this structure Black increases his central control and often gets play on the kingside (the recent game Colding-Krush annotated on Chesspublishing.com is a model, although from a different move order). I think White should only allow this if he has an immediate tactical follow-up, usually against e6.
3) Exchanging on d5 in such a way that White must recapture with the pawn, thus giving Black a mobile kingside pawn-majority. It is maybe strange that White allows this at all, but sometimes Black can start a skirmish on the queenside to misplace White's pieces first and then exchange.
4) Playing on the kingside with ...Kh8 and ...f5, usually after an exchange or two on d5 to reduce White’s tactical chances in the centre. I think of this as Black’s last resort if White has coped with Plans 1-3, and it can be very effective not least because many White players assume only they have attacking chances. Black threatens to get serious play on the f-file and against g2. The move ...Qe8 is usually an important part of this plan, to stop tactics based on Nxe5, overprotect Nc6, and prepare to swing the queen over to g6 or h5. This is a main reason I don’t like committing to Qc7 early.
First,
12.Rd2. It has become apparent to me that you are finding the same holes in Palkövi as I have, but whereas I stopped there you are looking for improvements for White as well!
My interest in
12...Ng4 was largely based on that hole in Palkövi (14.Nxe7? Na5), but I agree
13.Nd5 Nxe3 14.Qxe3 has to be better. In my old notes I then intended Plan 1)
14...Bg4 to gain access to d4 for the knight, but Black's material advantage seems difficult to convert with Bc4 becoming such a strong piece. White is at or very close to full compensation.
14.Nxe3 obviously stops Bg4, but after
14...0-0 I imagined the knight would not stay on e3 for long. Looking at it now, probably White can employ some prophylactic thinking and eliminate Black's idea entirely.
So,
12.Rd2 0-0 13.Rad1 h6 remains my main response. While
14.Nd5 is better than Palkövi’s 14.Nh4, Black should of course not fall for the Bc5 trick, but instead play Plan 4):
14...Nxd5 (14...Nxe4 15.Bb6 Nxd2 16.Bxd8 Nxf3+ 17.Qxf3 Bxd8 18.Qa3 is interesting, Black nominally has enough for the Queen but to me this looks hard to win for either side.)
15.Bxd5 (15.exd5 looks just silly with two rooks on the d-file)
15...Qe8! 16.a3 Kh8! Intending ...f5. White’s pieces don’t threaten anything in the centre, and while Black’s extra pawn on d6 looks a bit irrelevant at the moment, it is a useful ”endgame insurance” if Black can’t break through on the kingside. White has not equalized here.
White’s troubles in this line lead me to think your novelty
12.b4!? deserves strong consideration. Since this is already a monster post I will leave further discussion of that till later and just note that 12...0-0 intuitively appears the most sensible reply to me.