|The Nimzo-Indian Defence is a chess opening characterised by the moves (in algebraic notation) 1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 (other move orders, such as 1.c4 e6 2.Nc3 Nf6 3.d4 Bb4 are also feasible). In the Encyclopedia of Chess Openings scheme, the Nimzo-Indian is classified as E20-E59.|
This hypermodern opening was developed by Grandmaster Aron Nimzowitsch who introduced it to master-level chess in the early 20th century. Unlike most Indian openings the Nimzo-Indian does not involve an immediate kingside fianchetto but instead Black attempts to undermine White´s pawn centre using his bishop and doing so inflict doubled pawns. White will attempt to create a pawn centre and develop his pieces to prepare for an assault on the Black postion.
The delay in Black committing to a pawn structure means the Nimzo-Indian is a very flexible defence to 1.d4 and can also transpose into lines of the Queen´s Gambit or Queen´s Indian Defence.
White usually responds with one of the following moves:
- 4.Qc2 - The Classical Variation is one of the soundest variations. White avoids doubled pawns because after a ...Bxc3 capture, White can recapture with the queen. The downside is that White developes the queen quite early, and Black will be able to get a slight lead in development.
- 4.a3 - The Sämisch Variation (named after Fritz Sämisch) is the most aggressive response. Black is now almost forced to play 4...Bxc3+, inflicting doubled pawns on White because 4...Ba5?? loses the bishop to 5.b4 Bb6 6.c5, and 4...Be7? allows White to establish a powerful center by 5.e4. As compensation for the pawn weakness, White hopes to establish a powerful centre, which will provide a basis for a quick attack before Black can make use of the strategic advantages. Black has to defend against the attack, keep the white center at bay, and will usually aim to win the weak white pawn on c4.
- 4.e3 - The Rubinstein Variation (named after Akiba Rubinstein) is the most common variation. White prepares to develop the kingside, and strengthens the centre slightly.
- The "Normal Variation" is now 4... 0-0 5.Bd3 c5 6.Nf3 d5 7.0-0. White has made natural and sound developing moves while Black has launched an attack on the centre.
- The "Hübner Variation" is 4...c5 5.Bd3 Nc6 6.Nf3 Bxc3+. This has become a popular line for Black. At first, it looks as if Black is playing a Sämisch Variation, a tempo down since White has not played a pawn to a3, but Black´s strategic justification is that White´s knight stands somewhat poorly on f3, where it blocks the f-pawn, delaying establishment of a large pawn centre.
- White often plays Ne2 instead of Nf3, in order to be able to recapture on c3 with a knight.
- 4.Bg5 - The Leningrad Variation is an aggressive line which has been played, among others, by Boris Spassky. White developes a bishop to an aggressive square where it pins the Black knight. The plan is usually to play aggressively on the kingside.
- 4.Nf3 - The Kasparov Variation is named after Garry Kasparov. White developes a knight to a natural square, but holds back the e-pawn for a while, thereby avoiding the Hübner Variation.
In the Encyclopaedia of Chess Openings, the Nimzo-Indian Defense has codes E20 to E59.