Figure[White to move]

A last example of the defensive implications of our current theme. Black just played c5xd4. If White plays Nxd4, the natural recapture, his knight and bishop are poised to be forked by Black’s e-pawn. (We will study this pattern closely in the chapter on pawn forks.) Perhaps White shouldn’t worry about this, because if Black plays e7-e5, White can just play Bxe5. Or can he? Again, White should not play in the middle of this board without noting that White’s d-pawn and Black’s c-pawn both have been moved. That means anything White leaves on the fifth rank at the end of an exchange is likely to get taken in a fork by Black’s queen. Bxe5 indeed would have that effect, losing the bishop when Black plays Qa5+. So White would have no good answer to the pawn fork e7-e5, and dares not play Nxd4 in the first place.