Amakusa bankan citrus is the latest blooming citrus. It is very juicy, refreshingly sour and offers a refined sweetness. Coming from the family of buntan citrus and grapefruit and also known as Japanese grapefruit, bankan citrus was accidentally discovered in Kawachimachi, Kumamoto in 1935 and registered as Kawachi bankan citrus. The ones produced in Amakusa, the main production location, are called Amakusa bankan citrus. It has a rich flavor and is very juicy and refreshing. Amakusa bankan citrus peel is made by boiling the outer skin of the citrus and candying it over a few days.