Queen's Pawn Game: Colle System, Grünfeld Formation

The Queen's Pawn Game: Colle System, Grünfeld Formation is a chess opening classified under ECO code D04 in the Closed & Semi-Closed Games family, arising from 1.d4 d5, including the Queen's Gambit, Slav Defense, and related systems. It is reached after 4 moves: 1. d4 d5 2. Nf3 Nf6 3. e3 g6 4. Bd3 Bg7. The resulting position leaves white to move.