Blachly Gambit

The Blachly Gambit arises when Black, having chosen the MacLeod Defense with 3...Nc6, answers 4. Bc4 with 4...g5. The pawn advance gives f4 the pawn support it lacks after a quiet knight move. It also prepares ...g4 to drive the f3-knight away, which would weaken White's control of h4 and e5. The position resembles the Classical Variation, except that Black has already developed the queen's knight and White's bishop already bears down on f7. White is still a pawn down and must find play before Black's kingside pawns gain more ground.

The most frequent reply is 5. O-O, which brings the rook to the half-open f-file and accepts that ...g4 may follow. 5. d4 claims the center and opens the c1-bishop's diagonal toward f4. 5. h4 challenges the pawn chain at once and gives White the best practical results of the three. The engine prefers Black slightly, with d4, h3 and O-O as its top choices for White. In online games the results are almost even, and very few end in draws.