Finishing a won game

Being ahead in material means nothing if you can't deliver the final blow. A few basic checkmates come up again and again — two rooks, king and queen, and king and rook — and each is a forced win once you know the technique. The common thread is fencing the lone king to the edge of the board, where it runs out of squares.

Two rooks can do this by themselves, 'laddering' the king back one rank at a time. A single heavy piece, though, needs help: your own king must march up to take away escape squares so the queen or rook can mate. In the diagram, the two kings stand face-to-face — that 'opposition' is what lets the rook deliver mate along the back rank.