The King's Indian Defence is a common chess opening. It arises after the moves:
Black intends to follow up with 3...Bg7 and 4...d6. The Grünfeld Defence arises when Black plays 3...d5 instead, and is considered a separate opening. White's major third move options are 3.Nc3, 3.Nf3 or 3.g3, with both the King's Indian and Grünfeld playable against these moves.
The Encyclopaedia of Chess Openings (ECO) classifies the King's Indian Defence under the codes E60 through E99.