In answer, I had to look up the line since it's not part of my repertoire but 8. ...b4 is and has been played. The move was hazarded by Sherman against Fischer in: Fischer - Sherman (USA ch (7) 1957) and also by Van Wely against Short in Short - Van Wely (rapid game 1994) as two examples. White won both games and in neither game did Black take the pawn on e4, which seems logical since it sets up a rook move to the e-file with tempo thus putting additional pressure on e6. Fischer moved the Knight back to b1 and Short chose the supperior Knight move to a5.
There are a fair number of entries in our database with the b4 move and the results are reasonably mixed that Black could try it as a surprise against an unprepared opponent.
This should have a diagram, but I don't know how to make one and am too lazy to try to figure it out.
But I was hoping some Najdorf players could tell me why an eighth move by black of 8) ... b4 is never played in the mainline.
After 1) e4; ...c5 2) Nf3; ...d6 3) d4; ...cxd4 4) Nxd4; ...Nf6 5) Nc3; ...a6 6) Bc4; ...e6 7) Bb3; ...b5; 8) O-O ...
Why not 8) ...b4 to drive the white knight from c3 and capture white's unprotected e4 pawn?
Whenever I play against the Najdorf, I always play 8) O-O because that's the "book move" for white and hope black doesn't reply 8) ...b4 because I have no idea how to refute it. General opening books I've seen give white's best 8th move as O-O but don't say why 8) ...b4 is considered bad for black.
Anyone know?
I've never come across 8) ...b4 in a game.
Full disclosure: I'm playing white in a Najdorf now, but my opponent did not play 8)...b4 (my opponents never do for some mysterious reason.) If it's a breach of rules/etiquette to discuss, please don't. But the possibility of 8) ...b4 already passed and this is a question I've had for years.