Figure 4.5.3.4[White to move]

This position is the same as the last one, but with a Black pawn on c6 that blocks the bishop’s path to e8. Now what should White do? Answer (of course): examine every check. This leads you to Bb3, which forces Black to move his king (probably to c5). Ask what now becomes possible and you find the same skewering idea we saw a moment ago: Bf7, winning the exchange next move. In effect this position involves two skewers; with Bb3, White skewers Black’s king to the skewering square f7. The key here, as before, is to recognize that rooks on the same diagonal create a good target for a bishop or (sometimes) a queen. Once you see that possibility, whether right away or after the check, the rest is engineering.