Classical Variation, Charousek Variation

The Charousek Variation is Black's answer 4...Bb6 to the Central Variation of the Classical Ruy Lopez. Instead of waiting for d4 to hit the bishop, Black withdraws it at once, keeping it on the a7–g1 diagonal but spending a tempo. The most common reply is 5. O-O, while 5. d4 claims the center immediately and gives White the best results. Engines see a comfortable edge for White, and the line is rarely played.