It is illegal to distill or brew alcohol for sale without permit but you can consume homemade liquor at home. Homemade liquor is made by steeping fresh fruits, distilled alcohol(shochu made from molasses) and white rock sugar.
Most popular fruit is Japanese plum(ume) but strawberry, cherry, lemon and kumquat are also used for the liquor.
The volume of alcohol must be 35% or higher and if you do not have shochu, you can use vodka instead. Put all ingredients into a large jar and leave it at least for 1 month. Recommended to mix with still or sparkling water when consuming.