A checkmating pattern in chess, similar in style to a back rank mate except that the king is trapped on the side of the board. An enemy knight guards the two squares diagonally adjacent to the king, while his other flight square is usually blocked by one of his own pawns, allowing a rook or queen to give mate on the king's file. The name "Anastasia's mate" comes from the inclusion of this pattern in the 1803 novel Anastasia and Chess by W. Heinse. An example:
+---+---+---+---+---+---+---+---+
| | | | | |BR |BK | |
+---+---+---+---+---+---+---+---+
| | | | | |BP |BP |BP |
+---+---+---+---+---+---+---+---+
| | | | | | | | |
+---+---+---+---+---+---+---+---+
| | |WR |WN | | | |WR |
+---+---+---+---+---+---+---+---+
| | | | | | | | |
+---+---+---+---+---+---+---+---+
| | | | | | | | |
+---+---+---+---+---+---+---+---+
| | | | | | | | |
+---+---+---+---+---+---+---+---+
| | | | |WK | | | |
+---+---+---+---+---+---+---+---+
White wins by
Ne7+, forcing the king to h8, after which
2. Rxh7+ Kxh7 3.Rh5# is mate.