Nimzo-Indian Defense: Spielmann Variation, Stahlberg Variation

The Nimzo-Indian Defense: Spielmann Variation, Stahlberg Variation is a chess opening classified under ECO code E23 in the Indian Defences family, where Black responds to 1.d4 with 1...Nf6, including the Nimzo-Indian, Queen's Indian, and King's Indian. It is reached after 9 moves: 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qb3 c5 5. dxc5 Nc6 6. Nf3 Ne4 7. Bd2 Nxc5 8. Qc2 f5 9. g3. The resulting position leaves black to move.