Most mating patterns have a signature move or idea—a distinctive attacking position for one of your pieces, the potential for which can serve as a clue that the pattern may be available. For Anastasia’s mate the signature is the knight’s move to e7 (or, if the knight is Black, to e2) against the castled king. The move forces the king over to h8, and seals off both g8 and g6; it means the king is trapped on the h-file, so that an attack there by a heavy piece will deliver mate—perhaps after a sacrifice to open h7 (or h2 for Black). In the diagrammed position Black sees that his knight can get to e2, that his queen then will be able to get to h2 (and be sacrificed there), and that his rook then will be able to reach the h-file to close the deal. So he plays 1. …Ne2+; 2. Kh1 (forced), Qxh2+ (standard); 3. KxQ (forced), Rh4#. The potential queen and rook moves both were masked by the knight at the outset, but when a knight is posted this powerfully you always want to ask what effect its moves would have on the lines where it sits.