Catalan Opening: Closed, Sokolsky Variation

The Catalan Opening: Closed, Sokolsky Variation is a chess opening classified under ECO code E09 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 10 moves: 1. d4 Nf6 2. c4 e6 3. g3 d5 4. Bg2 Be7 5. Nf3 O-O 6. O-O Nbd7 7. Qc2 c6 8. Nbd2 b6 9. b3 a5 10. Bb2 Ba6. The resulting position leaves white to move.