E46: Nimzo-Indian, 4.e3 O-O

E46 Sub-variants:

• Nimzo-Indian, 4.e3 O-O
  1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O
• Nimzo-Indian, Reshevsky variation
  1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Nge2
• Nimzo-Indian, Simagin variation
  1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Nge2 d5 6. a3 Bd6