Enabling a future knight manoeuvre via f8.

Keeping the rook in order to enhance a future attack.

White should have restricted the enemy knight by 10.f5 , although Black maintains the initiative after d5.

With the idea of ...c6-c5. There followed:

and the white king proved fatally exposed.

Activating the last piece, without worrying about the doubled f-pawns.

Thanks to his strong first move White now possesses a powerful passed pawn.

Vacating the c4-square for the rook.

This and the next move eliminate Black's more active pieces and weaken his defence of the crucial c8-square.

Removing the annoying pawn on d3 and enabling a future attack with Rh4.