The marking on the right shoulder is emerging sumi and does appear to be coming up and not going down. Sumi seems to do well in my pond while hi generally suffers. I have two different ponds though and try to keep my better koi in the pond with a lower ph. And when I say lower ph I mean low 8's as opposed to high 8's. I have a whole series of pics of one of my shiros showing the sumi coming, going and coming back again but I posted it many times so here is shot of one of my showas which shows the sumi coming up over one season.
June 2006
November 06
Yes Wayne you could say I have a thing for shiros! Great looking shiro you have. Looking forward to seeing pics when she comes out of the pond in October.