Good bishop / bad bishop — what it means in chess
A bishop free of its own pawns versus one hemmed in by them.
A bishop free of its own pawns versus one hemmed in by them.
[[board startfen="rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1" caption="The French Advance, and the most famous prisoner in chess: Black's light-squared bishop on d7, staring at its own pawns on d5 and e6 — every one of them on its color." pgn="e4 e6 d4 d5 e5 c5 c3 Nc6 Nf3 Bd7" notes="A bishop is worth exactly what its diagonals are worth. Watch what Black's pawn structure does to the c8 bishop before it ever moves. White opens. The French — and with ...e6, the first bar of the cage. White builds. With ...d5, the second bar: two Black pawns now stand on light squares, the bishop's only color. White advances and locks the chains. Black counterattacks the base. White reinforces. Pressure on d4. White defends again. And here is the picture: the bishop develops to d7, its grandest available square — a light-squared piece behind a light-squared wall. French players spend entire games arranging this bishop's escape or its trade; the literature calls it the problem bishop for a reason."]]
Good bishop, bad bishop is the vocabulary for a truth about the game's most structure-sensitive piece: a bishop is worth what its diagonals are worth, and its own pawns decide that. A bad bishop stands behind friendly pawns fixed on its color — they block its lines and cannot get out of the way. A good bishop looks at pawns on the opposite color, its diagonals clear. Same piece, same square count, wildly different value; endgame theory treats good-versus-bad-bishop as a winnable relationship all by itself.
The Endgame Society glossary defines more than 240 chess terms — rules, notation, tactics, strategy, pawn structures, endgames, and openings — in language a beginner can act on rather than dictionary shorthand.