The Box Mate is a Rook + King Combo vs a Lone King. This is another basic checkmate that involves the technique of reduces the size of the 'box'. In the example below, the technique is demonstrated accurately - however, there are other ways of accomplishing this checkmate as well. The concept is to use your rook & king actively to drive the black king to one of the four corners of the board. Once the king's are directly opposite each other the rook then makes the only 'check' which also is the final blow (checkmate).