Sudachi is a small, round, green citrus fruit of Japanese origin that is a specialty of Tokushima Prefecture in Japan. It is a sour citrus, not eaten as fruit, but used as food flavoring in place of lemon or lime. Genetic analysis shows it to be the product of a cross between a yuzu and another citrus akin to the koji and tachibana orange.

Tokushima Prefecture is a prefecture of Japan located on the island of Shikoku. Tokushima Prefecture has a population of 728,633 and has a geographic area of 4,146 km2. Tokushima Prefecture borders Kagawa Prefecture to the north, Ehime Prefecture to the west, and Kōchi Prefecture to the southwest.