Undiluted Sake
In the sake brewing process, the final alcohol concentration will reach up to 20%. Most sake breweries will add water to dilute the alcohol concentration to between 14% to 17% before bottling. If the sake brewer doesn't dilute the sake, it will be called "Genshu," which means "original sake."
Genshu is quite extensive in terms of tasting. It is suitable for room temperature tasting and cold tasting. Some Japanese will also enjoy it on the rocks.