Both kohaku posted give me a scary feeling, the head pattern on the first photo B.Scott posted has obviosly receded in the first photo, let alone the second.
Doc Jims kohaku, I'm sure when he bought did not look so 'iffy' but in the photo posted, the maruzome kiwa looks a little frightening.
Signs to look out for.
Here is a snap of a famous kohaku I own which shows you the signs to look out for with regard to kiwa breaking up.
Maurice.