Nimzo-Indian Defense: Kmoch Variation

A solid and flexible chess opening for Black, focusing on controlling the center and creating imbalances in pawn structure.

The opening in question is a popular and well-respected choice that offers Black a solid and flexible setup against White's 1.d4. In this opening, Black aims to control the center with their pieces, rather than pawns, and create imbalances in the pawn structure that can be exploited later in the game. The key move in this variation is 4...Bb4, pinning the White knight on c3 and putting pressure on the central d4 pawn.

White's response, 5.f3, is an aggressive move that aims to support the central pawn duo and prepare for e4, expanding in the center. This move, however, weakens the kingside and can lead to potential problems if White is not careful.

Black's main idea in this opening is to provoke weaknesses in White's pawn structure, often by inducing doubled pawns on the c-file after an eventual ...Bxc3. Black can then target these weaknesses with moves like ...c5, ...Nc6, and ...Qa5.

White, on the other hand, will try to use their central pawn majority and space advantage to create threats and launch an attack. Properly handling the resulting imbalances is crucial for both sides in this opening.

The variation is named after the Austrian-Czech chess player and writer, Hans Kmoch. It has been played by many top-level players, including former World Champions Anatoly Karpov and Garry Kasparov, and remains a popular choice for players of all levels.