Checkmate can be delivered in countless ways, but if your opponent has castled the most common mating patterns fall into two broad categories. The first pattern, which we cover in this chapter, is the back rank mate. The general idea is to put a queen or rook onto your opponent's back rank and thus checkmate his king because its movement off the rank is blocked (usually by his own pawns). The “back ranker” is a common way for chess games to end, and we have seen it in passing many times in other chapters. (In the next chapter we will look at other mating patterns that involve attacking from above or along an angle.)
Back rank patterns generally are contests between two sources of power: your ability to drop heavy pieces (i.e., a queen or rook) onto your opponent’s back rank from above, and his ability to fend them off—most often with heavy pieces of his own sitting on the back rank, but perhaps also with a bishop or knight or queen that may protect the sensitive squares from farther up the board. This means that you often need more than one piece aimed at the back rank to make the pattern work: a first piece to sacrifice there that will force your opponent to use up his defenses, then a second or third piece to follow up with mate. The most common instrument for delivering such a mate thus is a battery of two heavy pieces on the same open file, with the forward piece either protected by the one in the rear or sacrificed to clear the way for it by removing a guard. Another typical pattern has a rook and queen coordinated against the same back rank square from different directions. But there are innumerable variations, as we shall see.
Begin with the simple study on the left. When the king is trapped behind its pawns and you have a mighty battery on the e-file like White does here, the immediate thought is a back rank mate. Against White’s three heavy pieces trained on e8 Black has two; he is outnumbered, so White wins with no trouble. 1. Qe8+, RxQ; 2. RxR+, RxR; 3. RxR#.