Shiroku-No-Gon
Part of what's fascinating about exploring shochu is that each distiller has their own approach to reaching flavor. The general rule is that if you want a smooth, mellow shochu you look for a shochu made with low pressure distillation and white koji. That combination is going to give you a very mellow shochu no matter what base grain is used. Conversely, a black koji and atmospheric distillation shochu is going to maximize flavors, create all sorts of complexity that many drinkers either love or hate. Where things start to get very interesting are in the middle.