Figure 2.2.15.6[White to move]

White has no checks or captures to consider. There remains one other sort of forcing move that at least partially dictates the enemy response: a threat, especially by a pawn; these tend to be very effective forcing moves because your opponent generally can't afford to lose a piece for a pawn. So try e2-e3. Where will the Black knight go? Look at the ring of eight light squares within its range, and see that only two of them are safe: b5 and f5. As usual after any sequence, you then ask what pieces would be loose, what lines would be open, and what attacks would be possible. Here the knight and bishop both would be loose (surely you saw the loose bishop from the start), and the movement of the e pawn would have opened a line for the queen. It is urgent that White look for ways to take advantage of those two loose pieces in the middle of the board. If the knight moves to f5, White can use the new open line to play Qg4, attacking knight and bishop at the same time. If the knight moves to b5, White can attack both pieces with Qa4.

The most important things about this problem are (a) not to overlook threats by pawns; they are forcing moves, and can cause big changes on the board—loose pieces and open lines; (b) to remember when thinking about White's second move that the e-pawn would be out of his queen's way; and (c) not to just assume the Black knight will “move somewhere” if attacked, but instead to examine its actual options and patiently consider what you could play in response to each of them. If the position were slightly different the fork at the end might not have worked; the knight might have been able to retreat to a safe square. But the benefits for White if the Black knight does end up loose are great, so a careful study of where the piece can go is fully warranted.