Anglo-Indian Defense, Grünfeld Formation

The Grünfeld Formation arises when Black, having started a kingside fianchetto with 2...g6, answers 3. g3 with 3...d5. This challenges White's c-pawn in Grünfeld style, although White has not yet committed the d-pawn. The usual reply is 4. Bg2, which completes the fianchetto and keeps the central tension. The next most common choice, 4. cxd5, resolves that tension at once, and 4. b3 is rare. The engine rates the position as roughly balanced. It is reached only occasionally, and White scores well in practice.