Choya plum liqueur is a Japanese alcoholic drink made from a type of plum called ume. The plums are soaked in a distilled spirit and sugar for several months, resulting in a sweet and sour flavored liqueur. It can be served chilled, on the rocks, mixed with soda water, or used in cocktails. Choya is a well-known brand of plum liqueur, and it's commonly enjoyed as a traditional aperitif or digestif in Japan. It's also used in cooking and baking and makes for a popular souvenir.