Kobayashi Koi Farm, listed in Japan as Marusen Kobayashi, is a small Shiro Utsuri specialist in Uonuma, Niigata, run by Naoto Kobayashi. ChampKoi imports koi from Marusen Kobayashi. If you want a Shiro Utsuri with white that is actually white, this is one of a handful of Niigata farms worth the search.
His Shiro Utsuri come from a line known as White Tiger, and the white is the point: clean shiroji without the yellow cast you see on a lot of young Shiro, on a body with more bulk than the variety usually carries. He also breeds Showa and a small number of other varieties, but the farm's name rests on the Shiro.
This is a small farm, and we count that as a plus. The breeder nets and grades his own fish, and volume is limited, so do not expect a long list from any one harvest. We could not verify a founding year, a pond count or a show record, so you will not find them here.
One housekeeping point: there are several Kobayashi operations in Niigata koi. The Marusen (丸仙) prefix is how the Niigata breeders' association and Japanese dealers identify this one, in Nakaie, Uonuma.