King's Indian Defense: Four Pawns Attack

The King's Indian Defense: Four Pawns Attack is a chess opening classified under ECO code E77 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 6 moves: 1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Be2 O-O 6. f4. The resulting position leaves black to move.