dom wrote on 04/30/11 at 11:39:48:
Plan for Black with Nd7 is to move this knight to c4...hence Qc4 seems to be not a precise move
9...Nd7 10.Nc3 Qc4 11.Bb2 Ne7 (11...a5 12.Qa4) 12.Rc1 Nc6 13.Ne2 Qb5 14.oo a6 15.Ne1! Nisipeanu-Ionescu,Calimanesti 1999 (Sevshnikov)
10...Qa6 11.Bd2 (mo need here to play Na4 because Nb6 is easy put off by b5) Qd3 (11...Ne7?! 12.a4 Sveshnikov-Alavkin,Cheliabinsk 2005 (Sveshnikov)) 12.Ne2 followed by oo and Nf4 giving White small advantage
10...Qc6 (most obvious way to engineer Black plan) 11.Na4! (Torre-Bagamasbad,Greenhills 1997 (Jovicic) ; to forbid Nb6 (Eingorn)) and now 11...a5!? (Sveshnikov-Grosar,Slovenie 2003) 12.Bd2 axb4 13.axb4 Qa6 14.Bc3 +=
I agree with your evaluation of 10...Qc6 and 10...Qa6 as being slightly better for White (although I would prefer 11.b5 after the latter), however, the Nisipeanu game doesn't change my opinion about 10...Qc4 solving Black's problems.
In the position after 15.Ne1 (!), why is Black worse after 15...Nc4? Also, I quite like 13...Qa6, to avoid being hit by Nc3 later. Black continues with ...Nc4, ...Nh6 etc.
13.Nd2 is probably a bit more testing, but after 13...Qd3 14.Na4 Nd7 15.Rc7 Rb8, although Black seems to be under pressure, it is hard to find anything convincing for White.
The other line after 10...Qc4, 11.Ne2, is probably well met by 11...Ne7, and while White's position may be a little easier to play, I find it hard to believe that Black is worse objectively.
Your argument, that 10...Qc4 is illogical because c4 is the square for the knight misses the fact that Qc4 avoids the Na4-stuff (because of 11.Na4 a5!) as well as the b5-push, and after White has lost some time of kicking it away Black can put his knight on c4 anyway.