Nimzo-Indian Defense: St. Petersburg Variation

1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 b6 5. Bd3 Bb7 6. Nf3

Nimzo-Indian Defense: St. Petersburg Variation is catalogued under ECO code E43. It is reached after 6 moves (11 half-moves): 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 b6 5. Bd3 Bb7 6. Nf3. After the last move it is Black to play. White opens 1. d4. It is a named variation of the Nimzo-Indian Defense, which has 99 catalogued lines in total. 1 deeper line continue from here, listed below.

Position shown after the last move; Black to play.