Queen's Indian Defense: Fianchetto Variation, Nimzowitsch Variation

About this variation

Black plays 4...Ba6 against the fianchetto, hitting c4 at once. It is the modern main line and asks White to commit early.

The Nimzowitsch Variation of the Fianchetto line is 1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Ba6. Black's bishop attacks the c4 pawn, forcing White to defend it with b3, Qa4, Qb3, Nbd2 or Qc2. Each defense has a cost: b3 weakens the long diagonal, the queen moves take time, and Nbd2 blocks the bishop on c1.

After 5. b3, Black usually plays 5...Bb4+ 6. Bd2 Be7, luring White's bishop to d2 where it is less active, and then aims for ...c6 and ...d5. After 5. Qa4, Black often plays ...c5 or ...Bb7, and the queen on a4 can become a target. After 5. Nbd2, Black can play ...Bb7 or ...c5. After 5. Qc2, Black usually plays 5...Bb7, since c4 is now defended and the bishop does more on the long diagonal, and follows with ...c5.

White's plans include Bg2, O-O and Nc3, preparing e4 to gain space. White can also aim for a quick d5 in some lines, opening the long diagonal and cramping Black.

Black's ideas include ...d5 with ...c6 for a solid center, ...c5 to challenge d4, and ...b5 in some lines to open the queenside. Black aims to use the extra time gained against the c4 pawn to complete development comfortably.

A common mistake for Black is to keep the bishop on a6 for too long, where it can become a target after Qa4 or b4. A common mistake for White is to defend c4 in a way that leaves the queenside weak.

This line suits Black players who like solid structures with active pieces. White players need to know the main defenses of c4, since each leads to a different type of position.

One concrete line is 5. Qa4 c5 6. Bg2 Bb7 7. dxc5 bxc5 8. O-O Be7 9. Nc3 O-O, when Black has pawns on c5 and an open b-file, and White has the long diagonal. The game becomes a balanced fight over the d5 square.

It is one of the main lines of the Queen's Indian Defense.