I decided to make my own, even if I am breaking all the rules!
Here how I proceeded in the secrecy of my office (even my better-worse half does not know about it!):
Bought 1 kg of green “ume” (Japanese plums) from a local grocery, 1kg of “koorizato” (“Ice sugar”) at Tomitaya Saketen.
To which I added in the most extravaganta manner:
1 bottle (720ml) of Kumpai Meguriai Honjyozo (Kumpai Brewery/Shizuoka City)
1 bottle (720ml) of Sugii Shodai Saisuke Kome/Rice shochu.
I cleaned the ume/plums, dropped them in jar especially conceived for home-made shochu, added all the sugar and poured in the above two bottles.
I closed it tight, marked the date on the lid, put in a cool area away from the light and will wait until next winter!