Maruyama
Koi
Farm

Maruyama Koi Farm is in Yamanashi Prefecture; the farm's own company page gives its address in Minami-Alps City. It is run by Futoshi Maruyama, and the farm's own page says it has been in business for about 40 years. It is a Kohaku farm first and everything else second, and its Ginrin Kohaku also take size-class wins at the All Japan show.