Queens Pawn Game Colle System Discovered Attack Chess Puzzles

In the queens pawn game Colle System, a discovered attack usually appears after White builds the classic setup with d4, Nf3, e3, Bd3, and c3, then opens a line by moving a piece that was shielding another attacker. The defining feature is that one white piece, often the bishop on d3 or the knight on f3, steps away to reveal pressure on the enemy king, queen, or a pinned piece.