MNb wrote on 02/07/18 at 11:53:24:
No matter what you play against the Pirc, as long as Black refuses to play ...Nf6 you need something independent.
That's true, but Black Modern players have the option of transposing to the Pirc against many White tries. So if White combines 4.Bf4 against the Pirc with, say, 4.f4, 4.g3 or some form of Classical against the Modern, he in effect has to know two full repertoires against the Pirc (unless he's bluffing).
Therefore some other choices against the Modern are more natural partners for the 4.Bf4 Pirc:
- 4.Be3, since if Black transposes the Pirc, he has made the concession of losing the 4.Be3 c6 and 4.Be3 a6 options where he delays ...Bg7
- 3.c3 intending Bd3, since if Black continues in Pirc style, he has lost Pirc-only options like 1.e4 d6 2.d4 Nf6 3.Bd3 e5 (a main line) and the more offbeat 3...c5 and 3...d5
- 3.c4 (if happy with a KID) and 3.Nf3 d6 4.Bc4 (as in Shaw's 1.e4 book), since these lines are independent of the Pirc
P.S.: I have just accepted
an ordinary chessplayer's underlying assumption that 4.Bf4 is no good against the Modern. I guess some ...Nc6 line or "Tiger's Modern" style must be fine for Black.