Queens Pawn Game Colle System Hanging Piece in Chess

In the queens pawn game colle system, a “hanging piece” is a piece (often a pawn or minor piece) left unprotected so it can be captured without immediate recapture. A defining feature of the Colle setup is the solid queenside structure after moves like d4, Nf3, e3, Bd3, and c3, which can unintentionally leave targets on d4/c4 or along the d-file if you misplace a defender.