Suntory Yamazaki Distillery Cask Finish Umeshu Plum Liqueur (often just called Suntory Yamazaki Casked Umeshu) is a Japanese plum liqueur (umeshu) made at the famed Yamazaki Distillery, where ripe Japanese plums are aged in toasted Yamazaki whisky casks and blended with whisky-matured plum liqueur, giving it a rich fruity sweetness with subtle vanilla and woody notes from the barrel ageing: it’s not a whisky but a sweet, aromatic liqueur best served neat, on the rocks, or with soda