It seems to be an autumn sake that is only available in the region.
https://www.kyoto-np.co.jp/articles/biz/389759
Purchased last year at Kyoto station
Matsue City, Shimane "Shinjuku Yakumo" Junmai Ginjo
Collaboration of Shimane sake brewer Li Bai and Keio Department Store
https://shop.keionet.com/goods/index.html?ggcd=SAKE-100002
Shinjuku Yakumo is an original brand sold exclusively at Keio Department Stores.
It is associated with Matsue in Shimane and Shinjuku, and named after "Koizumi Yakumo," a great writer who was active in introducing Meiji-era Japan to the world at large. We recommend this sake to those who are looking for a sake that will not interfere with your meal.
It is said that this sake was stored at the site of a former coal mine.
I heard that there is a similar old sake in Yubari, so maybe it is popular in Hokkaido.
The price is not cheap.
I asked him to choose one after consulting with a sommelier at the liquor store section in the basement of the Shinjuku Keio Department Store.
The same preference.
I asked the liquor store for some Konami sake for my friends to drink at the Koenji Awa Odori festival and they recommended it to me.
It tasted just the way I liked it.