Bishop's Gambit, Maurian Defense

The Maurian Defense answers the Bishop's Gambit with 3...Nc6. Black develops the queen's knight before committing to the early queen check, keeping the pawn on f4 and adding pressure against the d4 and e5 squares. Because ...Qh4+ remains available, play frequently transposes to the Cozio Variation (3...Qh4+ 4. Kf1 d6). The defense's standing has improved over time, and John Shaw went as far as calling it a refutation of 3. Bc4, judging Black better in every line. Engines agree that Black holds a slight edge.

The usual reply is 4. Nf3, which rules out the check. Black can then reinforce the extra pawn with 4...g5, and after 5. d4 Bg7 6. c3 d6 7. O-O h6 the game reaches the Hanstein Gambit, with a kingside pawn chain and a fianchettoed bishop on g7 opposing White's center and open f-file. The second choice, 4. d4, occupies the center at once and leaves the queen check in the air. It has given White somewhat better practical results than 4. Nf3. 4. Nc3 is rarely seen. In online play White's results remain favorable despite the engine assessment.