What is the name of the Japanese plum wine?

The Japanese plum wine is called umeshu.

Umeshu is a sweet-and-sour Japanese liqueur made by steeping unripe ume fruit in alcohol and sugar. Ume is often translated as “Japanese plum,” although botanically it is closer to an apricot. The base spirit is commonly shōchū, but other distilled alcohols may be used. Typical commercial versions contain about 10–15% alcohol by volume.

The fruit’s tartness and aroma balance the sugar, producing a mellow drink that can be served chilled, over ice, warm, or mixed with soda, tonic water, or tea. Some bottles contain whole ume fruits, which may be eaten after the liqueur has matured.

Umeshu recipes have been documented in Japan for roughly 300 years, with both home production and commercial manufacture established by the late Edo period. The label honkaku umeshu is used for versions made from real ume fruit rather than flavorings. Ramune is a carbonated soft drink, shōchū is a distilled spirit, and sake is a fermented rice beverage, so none is the name of this fruit-based liqueur.