Good Bishop / Bad Bishop

A bishop is classified as 'good' or 'bad' based on its mobility relative to its own pawns: a good bishop has most of its own side's pawns fixed on squares of the opposite color, leaving it open diagonals to operate on, while a bad bishop is hemmed in by its own pawns fixed on the same color it travels on, severely restricting its scope. This matters strategically because a bad bishop often becomes a long-term structural weakness, especially in endgames, as it can struggle to defend pawns or create threats and may simply be reduced to a passive defensive role. A classic example arises from certain pawn structures, such as when a player's central pawns sit on light squares while their remaining bishop is also light-squared, trapping it behind its own pawn chain; the French Defense's light-squared bishop (hemmed in by pawns on e6/d5) is a frequently cited case. Recognizing this imbalance guides strategic decisions like which minor piece to trade, when to fix pawns on a particular color, or how to maneuver a bad bishop to a more active diagonal or trade it off before it becomes a liability.