As a bit of a tag-a-long to JR's post, we have a former Gin Bekko male that displays some of what he touched on.
His sumi has always been a bit on the weak side, but well placed. The luster of his skin indicates the very high likelihood that he is the product of a purachina cross as his head was brilliant silvery white with a modest metallic sheen to the entire body.
Over the past 2 years (we've had him for 4) he has slowly developed a dorsal hariwake pattern
that began as yellow and has slowly moved toward a Yamabuki looking scale rather than ki. Along with that, he now has yellow eyelids on his otherwise clear white face. The Yamabuki in the woodpile is asserting itself more as he matures, and in the end he will very likely have a very hard hariwake look with weak bekko sumi. Lets just say he's "unique"
