Hiroharu Sato (#53689)

[whatkind]

Chances are that H.Kohshun(H·Kohshun) on some Chihiro Yonekura's albums might be this person.

This Instagram isn't currently active, and it's uncertain if it's his account. However its site title displayed in google search is '佐藤広春 (@h.kohshun)'.
https://www.instagram.com/h.kohshun/

In Japanese name reading, hiroharu is a Kun'yomi reading of 広春, and Kohshun(kousuke) is an On'yomi reading of it. H. might be the first letter of his given name Hiroharu.