Pinned pawns, of course, frequently are close to the king, providing cover for it and defending squares nearby. Paralyzing those pawns can do more than leave pieces loose, as in the previous studies; it can make squares available that permit a mating attack. It thus pays to experiment with ways of putting your pieces en prise to any pawns pinned in the king’s vicinity. This practice helps offset the psychological tendency to think of squares as off limits because they appear to be protected, when in fact their defenders are pinned and inert. Pins of pawns in front of the king along diagonals, sometimes from a long distance, are especially common and worth careful study. Those pawns often are supposed to be stopping pieces from landing too close to the king—but really aren't.
In the position on the left, a scan of the White king’s lines reveals a pin of the sort just described against the pawn on b2. So look for pieces and squares the pawn is supposed to protect, and see that the knight on a3 effectively is loose. More than that, play the capture (and check) RxN in your mind’s eye and see that White’s king has nowhere to go; its position is terrible, as it is backed into the corner of the board with no flight squares. RxN# thus ends the game.