Hence many endings of this sort finish in a draw. The win only becomes possible if the white king is near enough
Fair enough, but then he gives some diagrams with the "win zone" for the king, with no explanation of how they are drawn up. Is there a simple explanation for drawing up this "win zone" along the lines of the "square of the pawn" in king and pawn endings?
Apologies that there are no pictures with this post, they would explain my question much better and easier, but the ones I took appear to be too large to upload and I don't know enough to resize them.