 The variation with 7.Bg5 is named after Wolfgang Uhlmann, who played it a few times in the 1960s. Botvinnik also employed it in his 1960 world championship match against Tal. By pinning the knight, White aims to transpose into favourable lines of the Averbakh Variation of the King's Indian Defence, which may occur after 7 ... 0-0 8.Nd2 !. To prevent this, Black can either break the pin immediately with 7 ... h6 8.Bh4 g5 9.Bg3 Nh5, or after developing with 7 ... Bg7 8.e4 h6 9.Bh4. At this point 9 ... g5 10.Bg3 Nh5 runs into the pawn sacrifice 11.Bb5 + Kf8 12.e5! when White has a dangerous attack, and in the late 1970s this line was even thought to have refuted the Modern Benoni. Later it was realized that Black can prevent the bishop check with 9 ... a6 !: the only way White can forestall ... g5 and ... Nh5 is with 10.Nd2, but this allows Black to expand on the queenside with 10 ... b5 and reach a satisfactory position.
