Kabayaki (蒲焼) is a preparation of fish, especially unagi eel, where the fish is split down the back (or belly), gutted and boned, butterflied, cut into square fillets, skewered, and dipped in a sweet soy sauce-based sauce before being cooked on a grill or griddle.
Besides unagi, the same preparation is made of other long scaleless fish such as hamo (pike conger), dojō (loach), catfish, anago (conger eel), and gimpo (ギンポ) (gunnels). One can also find canned products labeled as kabayaki-style sanma (Pacific saury).
Kabayaki eel is very popular and a rich source of vitamins A and E, and omega-3 fatty acids. A popular custom from the Edo period calls for eating kabayaki during the summer to gain stamina, especially on a particular mid-summer day called doyō-no ushi-no-hi [ja] (土用の丑の日), which can fall anywhere between July 18 – August 8 each year.
The eel kabayaki is often served on top of a bowl (donburi) of rice, and called unadon, the fancier form of which is the unajū, placed inside a lacquered box called jūbako. It is also torn up and mixed up evenly with rice to make hitsumabushi [ja] (櫃まぶし), which is enjoyed especially in the Nagoya area.