A very common type of checkmate in chess where a king is trapped on the back rank behind a row of his own pawns, allowing an enemy rook or queen to checkmate simply by invading his rank:

+---+---+---+---+---+---+---+---+
|   |   |   |WR |   |   |BK |   |
+---+---+---+---+---+---+---+---+
|   |   |   |   |   |BP |BP |BP |
+---+---+---+---+---+---+---+---+
|   |   |   |   |   |   |   |   | 
.   .   .   .   .   .   .   .   .   

A slightly different pattern can occur when the queen gives mate on the back rank, since she can also attack the square diagonally ahead of the king:

+---+---+---+---+---+---+---+---+
|   |   |   |   |WQ |   |BK |   |
+---+---+---+---+---+---+---+---+
|   |   |   |   |   |   |BP |BP |
+---+---+---+---+---+---+---+---+
|   |   |   |   |   |   |   |   | 
.   .   .   .   .   .   .   .   .   

This type of checkmate often comes as a nasty surprise in amateur games, and many lost positions have been saved at the last minute when the opponent overlooks an impending back rank mate; however, the back rank mate is an important tactical theme at all levels of play.