Nimzo-Indian Defense: Normal Variation, Bernstein Defense

This chess opening is a solid and flexible defense that leads to a rich middlegame with chances for both sides.

The opening is characterized by Black's early development of the knight to f6 and the bishop to b4, putting pressure on White's central pawn structure. White typically responds with a pawn to e3 and the development of their own knight to f3 and bishop to d3. Black then castles kingside and plays d5 and c5, challenging White's central pawn duo. White also castles kingside and advances their a-pawn to a3, forcing Black to make a decision with their b4-bishop.

In this defense, Black captures the c3-knight, doubling White's c-pawns and potentially creating a long-term weakness. Black then exchanges pawns on d4 and c4, opening up the center and allowing for active piece play. White's doubled c-pawns can be both a strength and a weakness, as they can support a central pawn majority but also be targeted by Black's pieces.

Both sides have chances for active play in the middlegame, with White often looking to exploit their central pawn majority and Black aiming to create counterplay against White's pawn weaknesses. The opening is named after the Russian chess player Ossip Bernstein, who contributed to its development and popularization.