Yamagata's sake was designated a geographical indication in December 2016. It was the third such designation for sake, and the first in which an entire prefecture was taken as the unit; the two before it had drawn much tighter boundaries.

The rules are specific. Rice and rice koji must be domestic. The brewing water must be drawn within Yamagata. Brewing, storage, and bottling all have to take place in the prefecture. Any added alcohol must not exceed fifty percent of the weight of the rice, koji included.

The case made for the place rests on snow and on stone, which is to say on things nobody chose. Winters here bury the province, and the groundwater coming off these mountain ranges is soft and low in iron, which is credited with producing sake that is gentle and clear rather than heavy.

Yamagata has also bred its own brewing rice varieties over the years, among them Dewasansan and Dewanosato, so the raw material is local in a stricter sense than the written rules actually require. One caution on the date: the National Tax Agency's own list of designations carries a later date against Yamagata than the December 2016 announcement does.