Alapin Defense

The Alapin Defense, 3...Bb4, is an uncommon third-move choice for Black against the Ruy Lopez. The bishop copies White's Bb5 but has no clear purpose. Everything it eyes is already protected, and it does nothing to ease the pressure on the knight that guards e5. Engines give White a clear advantage, and White scores well in practice.

The most frequent reply, 4. c3, attacks the bishop at once and prepares d4 to open the center while Black's piece is exposed. Almost as popular is 4. Bxc6, which surrenders the bishop pair to leave Black with doubled pawns after either 4...bxc6 or 4...dxc6. Straightforward development with 4. O-O is the third main option. The line 4. c3 Ba5 5. Bxc6 dxc6 is known as the Alapin Gambit. The opening is generally regarded as dubious and appears mainly as an offbeat surprise rather than a serious defense.