It may not be a familiar citrus in some areas. Hebesu is a type of citrus that originated in Hyuga City, Miyazaki Prefecture. It tastes similar to sudachi and kabosu, but has a softer acidity.
The hebesu has a larger fruit ball than sudachi, a gentler aroma than kabosu, and a thinner skin than yuzu, and it produces a lot of juice.
Its skin changes color from blue to yellow as it ripens, and its aroma changes as it ripens.  
JAS certified organic hebesu from Nariai Hebesu En in Hyuga City, Miyazaki Prefecture, the place of origin.
The hebesu peels are peeled when they begin to turn from blue to yellow and distilled in a basket to give the gin a soft green citrus aroma, and the fruits are soaked in the first batch of raw sake before distillation to create a gin with a fresh juice taste.