Since the Edo period, this food has been valued as one of the three delicacies of Japan along with sea urchin and salted and dried mullet ovary. In Nanao City and Anamizu Town, sea cucumbers are left in corves for some time so that they expel mud thoroughly, and then, any remaining mud in the guts is removed completely by hand or chopsticks. After that, they are salted for a few days to be matured. During this process, the digestive enzymes in the intestine decompose the proteins contained in the intestine, and glutamic acid, a substance for umami (the fifth taste sensation), is produced, and it produces the rich smell of the ocean and its distinctive taste. It is usually eaten with rice or sake.