Opposite-colored bishop - Chess concept
Opposite-colored Bishops
Definition
An opposite-colored bishop (often shortened to “OCB”) situation occurs when each player retains one bishop and the bishops travel on squares of opposite colors—one bishop is confined to the light-squared diagonals while the other bishop patrols the dark-squared diagonals. In other words, the two bishops can never directly confront or capture each other because they live on mutually exclusive color complexes.
How It Arises
- Through early trades: 1. e4 e5 2. Bc4 Bc5 3. Bxf7+ …, etc.
- Typical pawn-structure transpositions, e.g. the Exchange French, Caro-Kann Advance, or certain Sicilian endgames.
- Simplification in queenless middlegames or late endgames where all minor pieces but one bishop per side are exchanged.
Strategic Nuances
Endgames: Because each bishop controls only half the squares, it is almost impossible for one side to drive the opposing king away from the other half. The defender can often build an impregnable fortress, making many opposite-colored bishop endings notoriously drawish, even with a material deficit of one, two, or sometimes three pawns.
Middlegames: Paradoxically, the same imbalance can increase winning chances for the attacker when queens or rooks are still on the board. Each side can place pieces on the color complex the opponent’s bishop cannot defend, creating “one-way traffic” against the enemy king. Famous sacrificial attacks often hinge on this property.
Typical Plans
- Defender (Endgame)
- Create an unbreakable blockaded line on the squares your bishop controls.
- Place pawns on the same color as the opponent’s bishop to immobilize it.
- Centralize the king and avoid pawn moves that create targets on your weak color.
- Attacker (Middlegame)
- Open lines toward the enemy king on the squares the opponent’s bishop cannot guard.
- Coordinate heavy pieces (queen, rooks) with your bishop to form a battery on the “good” color complex.
- Use pawn storms to pry open the opposing king’s shelter.
Historical & Notable Games
• Kasparov – Karpov, World Championship 1985 (Game 16)
In a queen-and opposite-colored bishop middlegame, Kasparov’s dark-square
domination on g7-h8 led to a crushing direct attack. This pivotal victory helped
him clinch his first world title.
• Tal – Botvinnik, World Championship 1960 (Game 6)
Tal sacrificed material to reach a position with opposite-colored bishops plus
heavy pieces, proving that the defending bishop could not cover both color
complexes. Botvinnik resigned after a spectacular mating net.
• Karpov – Unzicker, Nice Olympiad 1974
Illustrates the defensive side: Karpov calmly held a pawn-down endgame by placing
all pawns on dark squares opposite his own light-squared bishop, rendering
Unzicker’s bishop ineffective.
Illustrative Mini-Example
The following micro-endgame shows how two extra pawns are still insufficient:
Interesting Facts & Anecdotes
- Grandmaster John Nunn humorously calls opposite-colored bishop endings “an instant draw button” in practical play—but warns students never to push that imaginary button while queens are still on!
- During the famous Kasparov vs. Deep Blue rematch (Game 2, 1997), Kasparov resigned in a position later proven drawn because he underestimated the drawing power of opposite-colored bishops coupled with perfect computer defence.
- World Champion Emanuel Lasker reportedly advised club players: “If you’re up a pawn, avoid opposite bishops; if you’re down a pawn, seek them out.”
Key Takeaways
- Same material but opposite squares = imbalanced middlegame yet drawish endgame.
- Always evaluate king safety and the presence of heavy pieces before assuming a position with OCBs is automatically drawn.
- Good technique involves placing pawns on the square color opposite your own bishop to maximize its scope and restrict the rival bishop.