Tokushima is one of the prefectures in Shikoku Island, whose name of the capital is also Tokushima (徳島). As is often the case with Shikoku, the weather is very mild and warm, so they produce a kind of citrus called Sudachi (すだち) in Tokushima. It is a bit sour, green citrus, but it is an essential flavor for Japanese cuisine.
Tokushima
Area Map
