Exploiting a Bad Move in the Richter-Rauzer Variation of the Sicilian Defense
1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 d6 6.Be3 Bg4?! 7.f3 Bh5 8.Qd2 Nxd4 9.Bxd4 e5?
Hansen, Carsten. Catastrophes & Tactics in the Chess Opening - Volume 6: Open Sicilians: Winning in 15 Moves or Less: Chess Tactics, Brilliancies & Blunders in the Chess Opening (Winning Quickly at Chess Series) (p. 88). CarstenChess.
Regarding 6...Bg4?!, I tell my students to avoid developing their bishops when it allows the opponent to play a useful pawn move that chases away the bishop.
After 9.e5?, how can White best punish this mistake?