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.

Opening a new front on the kingside.

White soon won.

Before getting on with the kingside attack, Black prevents the opponent's idea of 2 Nc4.