The Japanese sansho pepper (山椒) is the seedpod of the Japanese prickly ash plant. Often ground into a fine powder, Japanese sansho is a spice used in many different dishes as well as one of the main ingredients that make up the seven-spice mixture, shichimi togarashi. These seedpods are more aromatic than they are spicy, but also have a slight numbing effect on the tongue that’s similar to the closely related Szechuan pepper.
Sansho can be purchased as whole seedpods to be ground fresh but are normally sold pre-ground since they easily keep their aroma. This spice is most commonly used to season grilled eel and chicken as it counteracts strong flavors and smells of fat. While the seeds of the sansho plant are very bitter and not used, the berries can be made into pickles. The young leaves of sansho, also called kinome, is another popular aromatic in Japanese cooking.
Sprigs of kinome serve as an edible garnish or herbal ingredient that can be chopped, crushed, or made into a paste. The little leaves are particularly used in suimono, aeomono, yakimono, and tsukemono. Kinome adds flavors that are similar to mint and basil with a touch of licorice.