is a dish originating in Japan. It consists of a donburi type large bowl filled with steamed white rice, and topped with fillets of eel (unagi) grilled in a style known as kabayaki, similar to teriyaki. The fillets are glazed with a sweetened soy-based sauce, called tare and caramelized, preferably over charcoal fire. The fillets are not flayed, and the grayish skin side is placed faced down. Sufficient tare sauce is poured over so that some of it seeps through the rice underneath. By convention, pulverized dried berries of sanshà  (called Japanese pepper, although botanically unrelated) are sprinkled on top as seasoning. It is also very popular outside of Japan, particularly in Taiwan and the United States.
Variations include unajà « (é°»éÂÂ, the same dish served in jà «bako (éÂÂç®±), food boxes often lacquered), nagayaki (é·ç¼ãÂÂ, the eel and rice are served separately), and hitsumabushi (ã²ã¤ã¾ã¶ãÂÂ, finely chopped eel kabayaki scattered (mabusu) over rice in a wooden rice container (hitsu) from Nagoya).
There are two styles of grilled eel, the topic of which is covered more precisely under kabayaki. Essentially, in the Kantà  region style, the eel is steamed before being grilled with sauce, which makes the eel more tender. The other is the Kansai region style, which is grilled without steaming.
Una-don was the first type of donburi rice dish, invented in the late Edo period, during the Bunka era (1804âÂÂ1818) by a man named of Sakai-machi (in present-day Nihonbashi Ningyà Âchà Â, Chà «à Â, Tokyo), and became a hit in the neighborhood, where the Nakamura-za and Ichimura-za once stood.
The first eatery to sell it as a business is claimed to be , in (adjacent to Sakai-chà Â) at some indeterminate time, but presumably before the theaters burnt down in 1841 and moved off. After the great famine of 1844, it started selling the unadon for one oblong Tenpà Â-sen coin, and became a hit.
As for unajà «, where the eel and rice is stuffed in jà «bako boxes, one theory ascribes its originator to one , who started a freshwater fish restaurant business in Sanya, Asakusa, Tokyo, called (later known as Jà «bako, the current generation of the restaurant is in Akasaka). According to this version the unajà « was already around by late Edo period, but there are detractors to this view. Other commentators say unajà « appeared in the Taishà  era, and by using lacquered boxes, aimed at appearance of luxury. Unajà « is usually pricier than unadon.