King's Indian Defense: Orthodox Variation, Classical System, Traditional Line

The King's Indian Defense: Orthodox Variation, Classical System, Traditional Line is a chess opening classified under ECO code E99 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 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O Nc6 8. d5 Ne7 9. Ne1 Nd7 10. f3 f5. The resulting position leaves white to move.