Spanish Variation

The bishop move puts pressure on the c6 knight, the guardian of e5, as in the Ruy Lopez (Spanish Game). The same position also arises from the Berlin Defense when White replies with 4. Nc3. The threat to win e5 is less real than it looks. After 4...a6 5. Bxc6, the Ranken Variation, 5...dxc6 6. Nxe5, Black cannot use the Ruy Lopez trick ...Qd4, because the c3 knight already covers e4. Instead Black plays 6...Nxe4 7. Nxe4 Qd4, forking both knights. This is the Spielmann Variation, which continues 8. O-O Qxe5 9. Re1 Be6 10. d4 Qd5 with material level. White can also retreat with 4...a6 5. Ba4, which transposes to a Ruy Lopez line.

The Double Spanish, 4...Bb4, is the principal reply in master play. After 5. O-O O-O White chooses among several named branches. The Symmetrical Variation, 6. d3 d6, leads to slow maneuvering, with offshoots such as 7. Bg5 Ne7, the Pillsbury Variation, and 7. Ne2, the Maróczy System. The Janowski Variation, 6. d3 Bxc3 7. bxc3 d6 8. Re1, gives White the bishop pair against doubled c-pawns. The Nimzowitsch Variation, 6. Bxc6, changes the structure early. With 6. Nd5 White breaks the symmetry, and 6...Nxd5 7. exd5 e4 is the Gunsberg Counterattack. The line goes back to the 19th century, and games from that era still shape its assessment. More recently it has been played by Nigel Short, Michael Adams and Alexei Shirov.

The Classical Variation, 4...Bc5, is the most frequent answer in online games. The bishop aims at f2, which gives Black tactical resources for holding e5 if White exchanges on c6. White usually castles. The alternative is the center fork trick 5. Nxe5 Nxe5 6. d4, which regains the piece and gains central space. A sharp branch after castling is the Bardeleben Variation, 5. O-O O-O 6. Nxe5 Nxe5 7. d4 Bd6 8. f4 Nc6 9. e5 Bb4.

The Rubinstein Variation, 4...Nd4, leaves e5 apparently loose so that the knight can counterattack f3 and break the pin pressure. It is the engine's preferred reply, and Black scores as well as White with it in online play. White's options include 5. Ba4, the traditional main line, the modern 5. Bc4, the simplifying 5. Nxd4 exd4, 5. O-O, the Henneberger Variation, and the pawn grab 5. Nxe5, the Bogoljubov Variation. The modest 4...d6, which defends e5 directly, is almost as popular online as 4...Bc5. Engines rate the starting position as level, and results in online games favor White only slightly.