Chess Opening Theory/1. e4/1...e5/2. Bc4/2...Bc5/3. Qg4

Boi variation C23 Boi variation 3. Qg4!? 3. Qg4!? is a rare sideline. Black's queen threatens to take on g7. If e.g. 3...Nf6? 4. Qxg7 and the two threats are Qxf7# and Qxh8. 4...Rh8++ is the only way to defend both. 3...d5?, attacking the bishop on c4 while discovering an attack on the queen, doesn't work as g7 is undefended. 3...Qf6 is Black's best way of defending g7. This also threatens to take on f2 (4. Nc3?? Bxf2+ 6. Kd1--). White can play 4. Nf3 to defend the pawn while developing a piece, though the knight is pinned to f2 until White castles, then 4...Nc6 allows Black's rook to see the bishop, so 5...d5! with a discovered attack on White's queen is now a threat. 3...g6 is playable but weakens the dark squares. Theory table References See also