Zanthoxylum piperitum, also known as Japanese pepper, Korean pepper, sanshō (山椒), and chopi (초피), is a deciduous aromatic spiny shrub or small tree, belonging to the citrus and rue family, Rutaceae. Natural range spans from Hokkaido to Kyushu in Japan, southern parts of the Korean peninsula, and Chinese mainland. The related Z. schinifolium (Japanese: イヌザンショウ pron. inuzanshō, lit., “dog sansho”) occurs as far south as Yakushima, attaining a height of 3 meters.
It is an important host plant for several Japan indigenous swallowtail butterfly species, including the common Papilio xuthus.