Nimzowitsch Variation

The Nimzowitsch Variation, also called the Nimzowitsch–Rubinstein Variation, has Black attack e4 at once with 2...Nf6 rather than preparing ...d6 or ...Nc6 first. The idea resembles Alekhine's Defense: White is invited to gain space by chasing the knight, and Black hopes to undermine the advanced pawn later. The critical reply is 3. e5 Nd5 4. Nc3. The Exchange Variation, 4...Nxc3 5. dxc3, gives White quick development, and Nimzowitsch's 5...b6 fails to 6. e6 f6 7. Ne5. The Main Line runs 4...e6 5. Nxd5 exd5 6. d4 Nc6 7. dxc5 Bxc5 8. Qxd5 Qb6 9. Bc4, after which 9...Bxf2+ 10. Ke2 O-O 11. Rf1 Bc5 12. Ng5 Nd4+ 13. Kd1 leads to sharp play in which White's chances are rated higher.

In practice 3. Nc3, the Closed Variation, is played slightly more often than 3. e5, while 3. d4 transposes toward open structures and scores well for Black online. Overall results are close to even, though the engine gives White a slight edge, and the variation remains a relatively uncommon sideline.