Scotch Gambit

The Scotch Gambit, 1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Bc4, postpones the recapture on d4 in favor of development. The bishop takes up its most active diagonal against f7, and Ng5 is often available to add pressure. Black cannot comfortably keep the extra pawn, so most lines turn on how and when it is returned. The position is also reached from the Italian Game, via 3. Bc4 Nf6 4. d4 exd4 or 3. Bc4 Bc5 4. d4 exd4, although the second order gives Black the extra option of 4...Bxd4. The engine rates the position as roughly balanced. White scores well in online games.

The most frequent reply, 4...Nf6, hits e4 and is the same position as the Open Variation of the Two Knights Defense. The Advance Variation, 5. e5, chases the knight. After 5...d5 6. Bb5 Ne4 7. Nxd4 Bd7 8. Bxc6 bxc6 9. O-O Bc5 10. f3 Ng5 White has regained the pawn. The Kingside Variation, 5...Ng4, is the main deviation. Instead, 5. O-O allows 5...Nxe4, a second pawn offer. The Anderssen Attack, 6. Re1 d5 7. Bxd5 Qxd5 8. Nc3, exploits the pin of the d4-pawn against the black queen and wins back the knight once the queen moves. The Perreux Variation, 5. Ng5, is a riskier try.

The Haxo Gambit, 4...Bc5, is the only way to defend d4 a second time. After 5. c3, returning the pawn with 5...Nf6 enters the Classical Giuoco Piano, where Black's game is considered satisfactory. The alternative 5...d3 also gives the pawn back while denying the knight c3. Accepting with 5...dxc3 runs into 6. Bxf7+ Kxf7 7. Qd5+ and Qxc5, after which White leads heavily in development. The Sarratt Variation, 5. Ng5, is regarded as premature. After 5...Nh6 6. Nxf7 Nxf7 7. Bxf7+ Kxf7 8. Qh5+ g6 9. Qxc5, material is level but White has spent many tempi. After 5. O-O, the reply 5...Nf6 6. e5 is the Max Lange Attack, and 5...d6 6. c3 Bg4 is the Cochrane-Anderssen Variation.

Among the other defenses, 4...h6 is a common practical choice that keeps the knight out of g5. The Benima Defense, 4...Be7, lets White recapture on d4 at once and steers toward Hungarian Defense positions; Black stays conservative but solid. The London Defense, 4...Bb4+, uses the moment when c3 is under Black's control and is among the engine's preferred moves. Its critical line, 5. c3 dxc3 6. O-O cxb2 7. Bxb2, leaves White two pawns down but with rapid development and active pieces as compensation.