This is dried ovary of sea cucumber. Since the ovary is very little, it needs about 20kg of sea cucumber to make one piece of the product. Thus, it is called the jewel of ocean, and is very expensive. It is made only in winter, when sea cucumbers are caught in Nanao Gulf. Thin thread-formed ovaries are hung on rope and formed into triangles with chopsticks. Since the shape resembles a pick (bachi) for the shamisen, it is also called bachiko. It is usually prepared by roasting it lightly. It is ideal as a dish for sake; the pungent taste of the ocean spreads in the mouth at every bite.