[2][3] When all of the attacker's pieces—apart from the king and pawns—contribute to a checkmate, this also means that none of the more powerful units have been left unused, an economical use of material.
All that is required is that all of the player's other remaining pieces—whether knights, bishops, rooks or queens—play a direct role in the attack on the mated king.
In his Dictionary of Modern Chess, Byrne J. Horton gave a similar definition: ECONOMICAL MATE: A term used by problem composers to indicate a mating situation in which every one of White's chesspieces on the board is utilized in some way, with the optional exception of the King and Pawns.
The Opera Game is frequently reproduced in chess primers as a tool to teach the importance of rapid development.
Anderssen allowed a double rook sacrifice in order to develop an attack using his remaining minor pieces.
[12] During the 1959 Candidates Tournament, Paul Keres lost a game to a young Bobby Fischer, which ended with a simple checkmate satisfying the conditions of economical mate.
As the black king contributed additional attacking force along the e-file, the final position was neither pure, model, nor ideal.