わらびもち
I couldn't wait to open the bottle after buying several bottles of a densely packed sake on a trip to the San-in region. It has an amber or slightly yellowish color, and the nutty and pickled ginger-like aroma gives it a sense of maturity.
The taste is a strong mix of sourness, umami, bitterness, and astringency when cold, but it mellows out when heated and is delicious. As the reputation goes, this is the kind of sake that "comes to life when it is heated up.
Sake in this direction is also enjoyable.
Postscript
As the store staff told me, if you let some time pass after opening the bottle, the aroma and taste will become rounder and more drinkable and delicious. It is the exact opposite of a fresh sake, and gives a sense of the breadth of sake.
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