also: ふるざけ
noun
aged sake; well-cured sake; old sake
Refers to sake that has been aged or matured, often implying improved flavor. Can also mean last year's sake in some contexts.
この居酒屋では、貴重な古酒を少しずつ味わえる。
At this izakaya, you can savor precious aged sake little by little.
古酒は熟成されてまろやかな味わいになる。
Aged sake becomes mellow through maturation.
Compound of 古 (old) and 酒 (sake). The reading こしゅ is the standard on'yomi, while ふるざけ uses the kun'yomi of 古 and the rendaku form of 酒.