Nimzo-Indian Defense: Three Knights Variation

1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.Nf3

ECO E21

The Nimzo-Indian Defense: Three Knights Variation is a chess opening line in the Nimzo-Indian Defense complex, reached after 1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.Nf3.

It is catalogued under code E21 in the Encyclopaedia of Chess Openings (ECO).

The defining move Nf3 is chosen by White on move 4.

3 named continuations branch from this position, including the Euwe Variation and the Korchnoi Variation.

Named variations

• Nimzo-Indian Defense: Three Knights Variation, Euwe Variation — ECO E21
• Nimzo-Indian Defense: Three Knights Variation, Korchnoi Variation — ECO E21
• Nimzo-Indian Defense: Three Knights Variation, Shocron Gambit — ECO E21

Study this line with a grandmaster

This position is covered in the Nimzo-Indian Defense course: a GM-authored repertoire you study move by move, then practice against a human-like AI opponent.

Every chess term used here is defined in the chess terms glossary. Browse all opening courses or the full ECO code index.