Sansho is a spice that is often sprinkled lightly on some Japanese soups, stews, and fish dishes. It is also an essential ingredient in shichimi togarashi.
The spice comes from grinding the ripened pods of the pricky ash. When the berries ripen, their pods split open, revealing a black seed. The black seed inside the pod is discarded, and only the split shell is used to make the spice. The prickly ash is native to the Szechuan region of China, which is why sansho is called ground “Szechuan Peppercorns” in English. The leaves of the plant are also used.