The Back-Rank Mate

The recipe: a castled king, its own unmoved pawns in front of it, and a back rank with no defender left. A rook or queen arrives on the 8th — and the pawn shield that kept the king safe all game becomes the wall of its prison.

This is the single most common checkmate in real games under 1600. You need it in both directions: to strike, and to see it coming at you.