Classical Variation, Berlin Variation, Steiner Variation

The Steiner Variation, classified as E38, is the reply 5...Bxc3+ to 5. dxc5 in the Berlin Variation of the Classical Nimzo-Indian. Black does not castle first, as in the Pirc Variation with 5...O-O. Instead, Black captures on c3 at once. This hands White the bishop pair in exchange for fast development. White must deal with the check immediately. White's extra c-pawns now stand doubled on c4 and c5, which gives Black a structural target while trying to recover the pawn.