What Black pieces are vulnerable to a pawn fork? His knight and bishop, of course. What are the obstacles? The Black queen, which blocks the pawn’s path; and again the pawn will need protection if it is going to attack a bishop. The problems here are the same as in the previous problem, and so is the solution: f2-f3 drives away the queen and also provides protection to support the fork e3-e4 that follows. (Note that after 1. f2-f3, Black has to move his queen somewhere; pay attention to where it will go, as its options are very limited. Black likely will play it to h4. Now White pauses to play the exchange 2. QxQ, g5xQ; he plays this first because his own queen is unprotected. Then he plays the fork in the middle of the board.)