There are three types in the raw.
Usually twice, a heat treatment (before and bottling before storage).
It called the "Namadume-shu" to not heated before storage.
It called the "Namachozo-syu" to not heated before bottling.
Saying "Honnama-syu" or "Namanama-syu" a drink that is not heated even once, this is the sake of the rare taste have excellent best flavor.

Here "Honnama-syu" only to introduce.