Figured I will post development updates for my Kobayashi Shiro, just as a learning tool. It wasn't an expensive fish, $150 when it was 5" in spring of 2015. Keep in mind that I live in a 4 season climate zone with cold winters so my feeding season is maybe 4 months a year with another 3-4 months of completely no feeding. I don't feed in order to push for growth either so growth of 3-5" per year is typical for me.
I have later read on this forum that for utsuri you can judge whether the sumi is up or down by how much sumi is in the pec fins - if there is a lot of sumi in pec fins then the sumi is up and vice versa. I have no idea whether that information is true or not but so far it turned out to be true for this fish.
4 months later, by September 2015 the fish was 10" but most of the sumi went down.
By next spring (May 2016) all of the sumi was back up. Actually even more sumi came up later.
By September 2016 the fish was 14" and the sumi was down again. This fish has a real talent for somehow scratching itself!
And the sumi has stayed that way ever since. The fish is now 17". Though there is some sumi visible under the skin on the body and on the face so I'm hopeful more will come up.
I definitely still like the fish. I think it is of nice quality for the price I paid. A bit more sumi would be great. Do you guys think more will come up?