FM Rumo @
Actually 7...a6 is the first preference for black in all theoretical discussions, books, lectures e.t.c but practically allows white to squeeze the Benoni.
Lev Psakhis turned out to use 7...Na6 with the idea after a4 from white , to jump on b4 and stop whites expansion but what happens if white don't play a4?! The knight gonna stay there for ever?! Quite funny.
7...a6 is currently the more popular move. But 7...Bg7 is fully playable. After the sequence 8.Qa4+ Bd7 9.Qb3 Qc7, black strives for a quick 0-0, Nh5 and f5. exf5 Bxf5 clears square d7 for the Nb8.
knight a6 if facing a3 by white hops to c7 ready for black to challenge the centre
Is Benko a variation of Benoni?
FM Rumo @
I sow your game and I want to ask something for the opening. I have been told that in this variation with 7.Bf4 the regular plan from black to play 7...a6 it's a positional mistake because after 11.Nd2 as you pointed out, white has the annoying plan to play a5 followed from Nc3-Na4 and eventually push b4-b5 while placing Rb1 behind.
What is your thoughts about this concept and how you counter this plan ?
Against 7.Bf4, 7...a6 is one of the two main moves. The point is to provoke 8.a4 and thus avoid the Qa4+ idea, that would otherwise slightly misplace black's pieces. You are right though that it gives white extra possibilities on the queenside, and it also takes away Ba6 and Na6 options from black. a7-a6 is a common move in the Benoni, but just inserting a7-a6 a2a4 for no particular reason usually favours white.