Back-rank mate

The back-rank mate is one of the first mates to learn, because it sneaks into games at every level. The rook or queen comes in along the back rank, where the king is shut in by its own pawns, and delivers mate. It usually turns up in the middlegame and in rook endings, once pieces have been traded and few of them are left watching that rank. The fight is usually over an open file: whoever has more pieces aimed at the square where the file meets the back rank wins it. To prevent it, all it takes is moving one of the pawns in front of the king in time, to give it an escape square. It looks like a wasted move, but it saves a lot of games.