Queen's Indian Defense: Classical Variation, Polugaevsky Gambit

The Queen's Indian Defense: Classical Variation, Polugaevsky Gambit is a chess opening classified under ECO code E17 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 8 moves: 1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. O-O O-O 7. d5 exd5 8. Nh4. The resulting position leaves black to move.