Opposite-colored bishops — what it means in chess
Bishops on different colors; drawish in endgames, dangerous in attack.
Bishops on different colors; drawish in endgames, dangerous in attack.
[[board startfen="1k6/8/1PK5/3B4/5b2/8/8/8 w - - 0 1" caption="A pawn up, king perfectly placed — and dead drawn. The promotion square is dark, White's bishop is light, and the Black king lives on the squares White can never touch." pgn="b7 Be5" notes="One bishop each, on opposite colors: they can never fight each other, never trade, never contest the same square. That fact is about to decide the game. The pawn advances to the edge of glory — b8 is one step away. And Black shrugs, sliding the bishop along its diagonal. The blockading king stands on the promotion square's approach, a dark square; the pawn needs b8, a dark square; and White's bishop is a light-squared piece forever. The White king may march anywhere it likes — every eviction it threatens happens on squares its bishop cannot cover. The extra pawn means nothing. Half the board belongs to each bishop, and they are different halves."]]
Opposite-colored bishops — each side's lone bishop living on a different color — create chess's strangest arithmetic: in the endgame they are the great drawing weapon, and in the middlegame they sharpen attacks. Both effects flow from one fact, visible above: the bishops can never contest each other's squares. Each side is effectively a piece up on one color and a piece down on the other.
In the endgame that asymmetry favors the defender enormously. The side down a pawn — often down two — parks the king and bishop on the color the enemy bishop cannot touch and blockades the passed pawn on a square of that same color, and no amount of maneuvering breaks in: the attacker's bishop attacks nothing relevant, and the defender's cannot be challenged. "Opposite bishops draw" is the club shorthand, and while exceptions exist — widely separated passed pawns being the classic one — the drawish pull is strong enough that a defender in trouble should steer toward the trade that leaves opposite bishops, and the winning side should avoid it like a tax.
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.