It's generally best not to do anything until you have satisfied yourself that you understand the enemy king’s position. Here as before, Black’s king is cramped—stuck on the back rank, almost ready to be mated by White with RxR. (Seeing this is just a matter of examining whatever checks you have.) In reply to that move, Black wouldn't be able to move his king or interpose anything; the only defense that would remain is a capture of the threatening piece, here with QxR. For this sort of case we have a mantra: When the only obstacle to mate is an enemy piece that would take your attacker, focus on the enemy piece. If it’s a minor piece, it may be as good as pinned and unable to perform other defensive service. If the crucial enemy piece is the queen, as it is here, consider attacking it.

In this case White has a few ways he might go after Black’s queen. Remember that Black’s goal in reply to any attack will be to move the queen to a square where it is safe and still protects f8. Thus, for example, in reply to 1. Rc1, Black can just play Qd6—or, better still, QxRc1+, winning the rook since the priority of check prevents White from taking advantage of the Black queen’s absence from c5. Much stronger for White, however, is 1. Qe5. Notice that this not only attacks Black’s queen but also attacks d6 and e7, two other squares the Black queen might like to use. True, Black still could play Qb4 and protect f8 from there; but then notice another property of Qe5: it creates an additional mating threat for White, aiming it at a square adjacent to Black’s king and already under attack by White’s rook. So if Black plays Qb4 in reply to Qe5, White plays Qxg7#; if Black instead plays QxQ, White has RxR#. Black does have a way to avoid mate: RxR. But this forfeits his queen, and so illustrates one of our general principles in this section: an attack on an enemy queen that defends against mate sometimes wins the piece, because your opponent has to spend time taking other measures to prevent the immediate loss of the game.

The difficulty in attacking the guard of a piece or square, as distinct from capturing it, is that an attack is not a forcing move in the same sense as a capture or check. A capture normally requires a recapture, which simplifies analysis. In reply to a mere threat against one of his pieces, though, your opponent generally has more options. He can add to the protection of the attacked piece (an often unsatisfactory course, however, when the attacked piece is a queen and/or when it plays a defensive role that its replacement will not be able to fill). More to our point here, he can simply move the attacked piece, and there may be many squares to which it can flee. The beauty of attacking a queen that guards a mating square is that its options for flight are limited: it can only move if it stays within range of the square it is required to protect, and sometimes you can cut off some or all of those alternative squares with the same piece that launches the attack.