Good Morning Larry!
If we are looking at the same thing, on the AJ GC then that is sashi or the insertion of white into the sumi area. And that can happen on any part of the body where deep sumi meets high class shiroji. In kohaku the Japanese often say that the blurred area of beni meeting shiro ground is a 'good thing'. This can be taken as a sign of quality color but the koi student needs to know why otherwise it is just a distraction from the crisp lines of color plates. So praising sashi is really an appreciation of quality elements of the right skin and the impressive depth of color ( beni or sumi). This is not to be confused with an unfinished fish in which color cells have not tightened yet as part of a natural maturity. This is the same lesson as understanding that all tategoiu are unfinished but not all unfinished fish are tategoi.
So we are talking about three subjects here:
1) kage patterned showa and shiros
2) unfinished sumi
3) sashi
Here is a shiro showing extensive true sumi. You can see on this fish that the sumi pattern is never going to fill in or turn this into an all black fish. The plot thickens here as there really are two types of kage, one arising from asagi reticulation and another from karasu and goromo. But at least this picture will allow you to see that 'kage' is as much about sumi patterns as it is about an area of sumi that might appear undeveloped by the casual eye.
And too be clear, 'kage' is often used by judges and breeders as a general description of a look and not a suggestion that a fish is truly a kage specimen. Not unlike calling a large bull, a 'real moose'!
