In chess parlance, the term pure mate refers to a checkmate (or occasionally a stalemate) where each square adjacent to the checkmated king is either occupied by one of his own pieces or attacked by exactly one enemy piece (but not both). A double checkmate, where in the final position two pieces attack the checkmated king, is usually considered impure. Here is an example of a pure mate, derived from a 1929 problem by Joseph Cumpe:
+---+---+---+---+
|   |   |   |WK |
+---+---+---+---+
|BK |BB |   |WR |
+---+---+---+---+
|   |BP |   |WB |
+---+---+---+---+
|   |   |   |   |   
+---+---+---+---+
|WR |   |   |   |
+---+---+---+---+

Note that this position disobeys the definition above, because the square to the king's right is both occupied by a black bishop and attacked by a white rook. However, this illustrates an exception to the usual rule, namely that if a friendly piece is pinned to the king which could otherwise prevent mate (as this bishop could, by moving to block the other rook's attack on the king), then the mate is still termed pure. Note that if the white bishop were replaced with a queen, the mate would be impure because the black pawn would then be under attack.

Pure mates occur most often in chess problems, where they are deliberately constructed for their aesthetic appeal; however they occasionally occur in real-world games. If a pure mate is also economical (as the position above is), it is termed a "model mate".

Log in or registerto write something here or to contact authors.