Also known as freshwater eel or simply eel. In Japanese, it is called "うなぎ" (unagi). Eels are born in the ocean, live in rivers, and when it's time to spawn, they return to the ocean to lay eggs and then end their lives. This type of fish is called anadromous. Conversely, fishes like salmon or smelt, which are born in rivers and live in the ocean and return to rivers for spawning, are termed as catadromous. In Korea, people eat chicken soup on specific days, whereas in Japan, people consume eel on a day called "土用の丑の日" (Doyou no Ushinohi). This tradition is said to have been started by a late Edo period scholar, inventor, potter, and pharmacist named Hiraga Gennai (1728-1780). One summer, an eel shop owner who was not doing good business sought advice from Gennai. In Japan, there was an old custom of eating foods starting with "う" (u) on "土用の丑の日," such as udon, umeboshi (pickled plum), and uri (gourd). Taking inspiration from this, Gennai suggested placing a sign in front of the shop saying "Today is Ushinohi." After this, people flocked to eat eel on this day, and other eel shops followed suit, establishing the present-day Ushinohi = eel culture. Hiraga Gennai, who also crafted various promotional phrases for eels

When you hear "Shirayaki," eel usually comes to mind. Grilled without sauce, the eel is enjoyed with wasabi and soy sauce, allowing you to fully savor its natural flavor. Because there is no seasoning to mask it, the true quality of the ingredient is revealed. The word Shirayaki (白焼き) comes from shira meaning “white” and yaki meaning “grill.” It refers to grilling an ingredient directly over a flame without seasoning, oil, or sauce. This method is also known as suyaki. It reduces excess fat, seals in umami, and enhances aroma, and is often used to create appetizing grill marks. While eel is most common, shirayaki is also used for cutlassfish, conger eel, pike conger, and even for dumplings like dango (rice flour dumplings).