The Power of the King or "How to crack a tough nut!"
Please look at the following position:
It is more than obvious that white has here a clear adventage. He controls the only open file with his rook(s) and his Nc5 and his Bc3 are well-placed. In contrary all black pieces seem to be occupied with defending tasks. So, will the win be only a question of time?
Surprisingly the white superiority will not lead "automatically" to a win. It seems hold the position with a passive waiting strategy. By the way, a strategy which is more often successful than you perhaps may think!
So what can white do to transpose his adventage into a win? How can he crack that tough nut? Well, as often in similiar positions the key is the answer of following question: Which piece isn`t active yet? Well, the answer here is easy, it is the King! His walk to the queenside and to the pawn b7 cracks the nut!