Assertion: checkmate's piece | /r/AtLocation | the board
Facets:
value: currently
type: TEMPORAL
Source sentences:
text: As far as I can tell, multiple pieces may be on the board so long as the stipulations of a pure mate are met.
text: For each turn, a player may either move a piece that is currently on the board (and potentially promote it, capture an opposing piece, or both) or else drop a piece that has been previously captured onto a square of the board.