In order to imprison Black's bishop just before he vacates the f8-square by ...Rfe8 or ...Rfc8.

From now White is basically a piece up and should just try to neutralize Black's temporary initiative.

Swapping the more active (to say the least) of Black's minor pieces. This also helps to improve his own bishop,

Finally Black is in zugzwang. There followed:

White soon won.

Imprisoning three black pieces on a6, a8 and b8.

Overprotecting the crucial d6-pawn.

Very clever. It is worth a pawn to swap off Black's active pieces, so that he is left with only bad ones.

5...Qxe4? 6.Bf3 +-

Despite his minus pawn, White is winning.