The terms "Unaju" (written as 鰻重, うなじゅう, うな重) refer to a Japanese dish, which contains broiled eel on rice with sauce in Jubako (generally tiered square wooden boxes with a cover which is coated by urushi Japanese lacquer) or refers to a specific kind of container used to serve broiled eel. Any of these terms are an abbreviation of unagi Jubako. Recently many unaju use the Jubako that is made of acrylonitrile-butadiene-styrene resin and coated with chemical coating.
In some regions, a bowl of rice topped with eel is called Unadon while rice topped with eel in Jubako is called Unaju. In other regions and restaurants, where the word Unaju means overlapped eel, rice sandwiched in between two broiled eels, that is, one eel is put on the surface of the rice and the other eel placed under the rice, is called Unaju.
How to eat
Generally, Unaju is consumed from the left corner by applying Sansho (Japanese pepper powder), which is considered to enhance digestion in Chinese medicine, which is dried and milled by a stone mill, in order to enhance the flavor. A proverb says, 'even small Japanese pepper is piquant,' and it is considered rude to put consummate amounts of powder, which can numb the taste buds. Generally it is often served with eel liver soup.
Shochikubai (pine, bamboo and plum trees)
Most Unaju are ranked using the terms of pine, bamboo and plum trees in the order of price. Ranking varies; in comparing the Unaju itself, ranks are based on the size of eel although there is a slight difference among individual eels; the ranks are also determined factors including whether the eel is served half or whole, and whether the eel is wild or farmed. Various factors are taken into account in this ranking system: whether two eels are arranged as described above or only one eel is used; and whether a whole eel is placed at the bottom layer when two eels are arranged as described above or a chopped broiled eel is placed at the bottom layer with, just like the Hitsumabushi (Nagoya style Eel on Rice), the edges which are cut off in order to cut the eel into evenly sized pieces included.
Since broiled eel is often cooked after an order has been placed, it is not a meal to be consumed when one is in a hurry. Some broiled eel restaurants begin to cook the rice after an order has been placed.
An esquamate fish including eel generally has a thick skin (unlike a catfish, eel has a very small squama which is hidden in the skin). A natural eel which lives in a river or pond is more elastic than a farmed or imported eel even after being steamed and broiled, and its taste more enjoyable due to its chewable nature. On the other hand, some natural eels cannot be cut by chopsticks as the usual farmed eel so that they have to be bitten off with one's teeth.
Hifumi KATO, a Kishi (professional shogi player) with nine dan (ninth grade), is famous for his preference for Unaju. He likes it so much that he eats Unaju when he plays a game, and it is said that he has 2,100 yen for Unaju for lunch and dinner in each of his left and right pockets.