Nimzo Indian Defense Classical Variation Discovered Attack in Chess

In the Nimzo-Indian Defense Classical Variation, a “discovered attack” happens when one piece moves away (often after a forcing exchange or pawn break), revealing an attack on a more valuable target behind it. The defining feature is the Classical setup with ...e5 and the pressure around the c4/d5 squares, where a tactical tempo can suddenly open a line to the king, queen, or a pinned piece. For example, a move that vacates a defender can uncover an attack on the c4-knight, the d5-square, or a piece on the d-file.