B51 Sicilian Defence: Moscow Variation

After 1.e4 c5 2.Nf3 d6 3.Bb5+, White gives check instead of opening the centre at once with an early d4. ECO code B51 covers this Moscow Variation when Black blocks with a knight: 3...Nd7 or 3...Nc6. The bishop check lets White develop quickly, castle and avoid the heavy theory of the Najdorf and Dragon. After 3...Nd7 Black keeps the option of ...a6 and ...b5 to question the bishop, and White can open the position early with d4 and Qxd4. After 3...Nc6 play often continues with ...Bd7, while White builds a centre with Re1, c3 and d4.