Opposite-Colored Bishops
"Opposite-coloured bishops are drawn" is one of chess's most dangerous half-truths. While these endgames have a strong drawing tendency, they are by no means always drawn. Understanding when the extra material wins, and when it doesn't, is essential endgame knowledge.
Why they tend to draw
Each bishop controls only half the squares. The defending side can place their pawns on squares the opponent's bishop can't attack and create a fortress. The extra pawn (or even two extra pawns) may not win because the defending bishop can sacrifice itself for the remaining pawns.
When the extra pawns win
- Passed pawns on both sides. The defending bishop can't cover both flanks simultaneously.
- Widely separated pawns. The further apart the passed pawns, the harder to defend.
- Active king position. If the winning side's king is more centralised and active.
- Three or more extra pawns. With enough material advantage, the fortress defence eventually fails.
The middlegame paradox
In the middlegame, opposite-coloured bishops actually favour the attacker! Because each bishop controls different squares, the defending bishop can't neutralise the attacking bishop's threats. The attacker has a "extra piece" in the sense that their bishop operates on squares the defender's bishop can't reach. This is why players sometimes seek opposite-coloured bishops when attacking.
Practical guidelines
When winning: Create passed pawns on both sides of the board. Keep extra pieces on (don't simplify to just bishops + pawns unless you must). When defending: Set up a fortress. Place pawns on the same colour as your bishop. Sacrifice the bishop for the last pawns if necessary. See also: Same-Colour Bishops and Bishop Endgames Guide.