Queen's Pawn Game: Colle System is a chess opening with the ECO code D05, part of the Queen's Pawn Game family. It goes 1. d4 d5 2. Nf3 Nf6 3. e3 e6. White opens with 1. d4 (the queen's pawn) and Black answers 1... d5. After 6 moves it is White to move. The lesson on the board explains every move of the line and lets you play it yourself; it is free.
In chessGM's opening book this position continues with 4. Bd3.
White opens with 1.d4 and plays a system without an early c4. It covers many calm setups like the Colle, London and Zukertort ideas.
chessGM has a full course for this line: open the Queen's Pawn Game: Colle System course lesson.