You can't expect a 10" Showa (with any future) not to be a little messy. Showa and SU lose a lot of Sumi from the time they are tosai through the development the next 3-7 years. Sumi reemerges and consolidates as they years go by. In an ideal world, the beni will hold, the conformation will be good when the Sumi is done returning.
The pics are a little challenging for eval, the bending shots in particular.
The Beni appears to be a decent quality and Sumi is okay. Don't judge the quality where it overlays the Beni, look for it where it is purely on the Shiroji.
The conformation is okay, the tail section is a little weak but that isn't uncommon unless it is of high quality. The head shape is much better than was common for Dainichi even a few years ago and that is a plus. I suspect it may be male, based on the density of the pec but it's young.
It's a nice little koi, enjoy it, take good care of it and post with updates.
Still learning as I go but y'all can call me Marilyn