Assertion: checkmate's piece | /r/HasProperty | involved
Facets:
Source sentences:
text: I recall seeing a number of chess games where a lot of pieces are involved in the final checkmate, and was curious to know what is the maximum number of pieces of one player A that have been involved in a checkmate of the other player B, where a piece is said to be involved if and only if removing it either causes B's king to be no longer in check or causes one of the squares around B's king to be no longer attacked by A's pieces.
text: It is easy to construct a reachable position where 9 pieces are involved, and to prove that no more than 9 pieces are involved.