"Asakura-zansho" (Zanthoxylum piperitum f. inerme) belongs to Rutaceae (the Citrus family). It is a small deciduous tree that is a variety of the Japanese pepper tree distributed in various parts of Japan and the Korean Peninsula. It is a mutation, characterized by its thornless stems and large, fragrant fruits. Its Japanese name comes from its abundance in Asakura, Yoka-cho, Yabu City, Hyogo Prefecture. It has been highly prized since the Edo period (1603-1868). Generally, the Japanese pepper tree is dioecious, but this species is monoecious and can bear fruit even on a single plant. Since the seedlings are indeterminate in sex and produce thorns, female plants are mainly grafted into cultivars for sale. It has been selected as a traditional vegetable of Hyogo Prefecture.