Normal Variation

The Normal Variation of the Nimzo-Indian Defense, ECO E46, arises when Black answers the Rubinstein System 4. e3 with 4...O-O, the most common reply at this point. Castling short commits Black to very little, since the king practically never goes to the queenside in this opening. It postpones the decision between ...d5, ...c5 and ...b6 until White has revealed how the kingside pieces will be developed.

White's most popular choice by a wide margin is 5. Bd3, aiming the bishop at e4. The Reshevsky Variation 5. Ne2 prepares to recapture on c3 with the knight, and 5. Nf3 is also common. After 5. Bd3 d5, the Classical Defense, 6. Nf3 c5 is the Gligoric System. Its Bernstein Defense branch runs 7. O-O Nc6 8. a3 Bxc3 9. bxc3 dxc4 10. Bxc4, handing White the bishop pair and a c3–d4 pawn chain. The Schlechter Defense is 6. Nf3 b6. In the Botvinnik System, 6. a3 Bxc3+ 7. bxc3, White accepts doubled c-pawns immediately. After 5. Nf3 d5, the Ragozin Variation, 6. a3 is called the Sämisch Deferred. The engine rates the position as roughly balanced, and online results are close, with White slightly ahead.