Nimzo-Indian Defence

The idea

A sophisticated, flexible defence and one of Black's most respected answers to 1.d4. Instead of meeting pawns with pawns, Black pins the c3-knight with the bishop and fights for the central squares — above all e4 — with pieces. Black is willing to give up the bishop for the knight to damage White's pawn structure and seize lasting control of the light and central squares.

Your plan (Black)

Pin and pressure the c3-knight, dispute the e4-square, and be ready to trade the bishop for the knight to leave White with doubled, vulnerable pawns. Strike at the centre with ...c5 and ...d5 once developed.

Heading into the middlegame

The Nimzo is a battle over e4 and White's pawns. Your bishop pins c3 and, at the right moment, takes it — saddling White with doubled, immobile c-pawns. Then play against them: clamp with ...c5 and ...d6, route a knight to a5 (or ...Na6–c7) to hit c4, and blockade the light squares (...b6, ...Ba6, ...Qa6 piling on c4). If instead you keep the bishop (Rubinstein), break with ...d5 and ...c5 for a classical centre fight. Either way: control e4, and make those doubled pawns a long-term target.