Japanese Eel Unaju and Kabayaki Technique

Japan — Tokyo (Kanto) and Osaka (Kansai) as distinct eel preparation traditions from Edo period

Unaju (鰻重, eel over rice in a lacquered box) is one of Japan's most celebrated summer foods, traditionally eaten on Doyo no Ushi no Hi (the midsummer Day of the Ox, usually late July) to combat summer fatigue — the rich protein, fat, and vitamin A content of eel was believed to fortify the body against the heat. The eel preparation follows a strict regional divide: in Tokyo (Kanto), the eel is split down the back, skewered, and steamed before grilling (mushiyaki) — producing an extraordinarily soft, yielding texture; in Osaka (Kansai), the eel is split down the belly, skewered, and grilled directly without steaming — producing a crispier skin and more pronounced charcoal flavour. Kabayaki (蒲焼) is the glazing technique applied to the grilled eel: a tare (secret sauce) of mirin, sake, soy sauce, and sugar is applied repeatedly during multiple rounds of grilling, building up layers of caramelised, glossy coating. The unaju tare, passed down through generations within eel restaurants (unagi-ya) without adding new stock — only replenishing — is considered part of the restaurant's identity. The grilling sequence for Kanto: grill over charcoal, steam 10–15 minutes, glaze with tare, grill again for 2–3 minutes, glaze, grill again — three to four glaze cycles produce the lacquered surface. Doyo no Ushi no Hi demand makes July–August the peak eel consumption season though cultivated eel is available year-round.

Rich eel fat rendered and caramelised under a soy-mirin lacquer, resting on hot steamed rice — a summer ritual of extraordinary luxury and restorative depth