Opera mate

The Opera mate is a coordination pattern built around a rook and a bishop. The rook attacks the enemy king along a horizontal row, called a rank, or a vertical column, called a file, and gives the final check. The bishop protects the rook along a diagonal, so the king cannot capture it. The remaining escape squares are controlled or, often, occupied by the defender's own pieces.

The defining feature is the final arrangement, not one mandatory move sequence. The rook must be able to enter safely, the bishop must support it, and the opposing king must have no legal escape. Sacrifices, meaning deliberate decisions to give up a piece or pawn, may be used to create the pattern, but they are preparation rather than part of the definition.

Why it is called the Opera mate

The name comes from Paul Morphy's famous 1858 consultation game in Paris against the Duke of Brunswick and Count Isouard, played during an opera performance. In a consultation game, two or more players jointly choose the moves for one side. In the final position, a rook delivered mate while a bishop protected it. The game made both the preceding combination and the final mating picture widely known.