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ECO E21

ECO E00–E99 — Indian Defenses: 1.d4 Nf6 with the Nimzo-Indian, Queen's Indian, Catalan and King's Indian complexes.

4 named opening lines are classified under ECO code E21.

Nimzo-Indian Defense: Three Knights Variation — 1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.Nf3
Nimzo-Indian Defense: Three Knights Variation, Euwe Variation — 1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.Nf3 c5 5.d5 Ne4
Nimzo-Indian Defense: Three Knights Variation, Korchnoi Variation — 1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.Nf3 c5 5.d5
Nimzo-Indian Defense: Three Knights Variation, Shocron Gambit — 1.d4 Nf6 2.c4 e6 3.Nf3 Bb4+ 4.Nc3 c5 5.d5 b5