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
{"Kanto technique: split back, steam before grilling — produces silky, soft texture by denaturing collagen before the grill caramelises the surface","Kansai technique: split belly, grill directly — produces crispier skin and more pronounced charcoal character","Multiple tare applications during grilling (kabayaki) builds the characteristic lacquered coating — each application burns slightly before the next is applied","Tare maintenance: never discard the foundation tare, only replenish — the oldest unagi-ya have tare pots with documented provenance of 100+ years","Unaju rice must be extremely hot under the eel — the eel warms from the rice below and the environment above; cold rice produces a cold eel"}
{"The best unagi-ya in Tokyo (Nodaiwa, Hashimoto, Obana) offer both Kanto and Kansai styles — ordering the Kansai variant in a Tokyo restaurant demonstrates knowledge that impresses","Hitsumabushi (Nagoya style) serves grilled eel over rice in a large wooden bowl (hitsu) for three eating styles: plain, with condiments (wasabi, negi, nori), then with dashi poured over","Unagi no kimo-sui (eel liver clear soup) is the traditional side dish accompanying unaju — a light dashi with grilled eel liver, mitsuba, and a thin ring of yuzu zest"}
{"Reheating unaju in a microwave — the microwave creates steam that softens the skin and destroys the kabayaki crust; reheat in a steamer or covered pan over very low heat","Using pre-made supermarket tare for kabayaki at home — commercial tare lacks the depth of a maintained saucepan reduction; home tare must be reduced slowly with high-quality mirin"}
Tsuji, S. — Japanese Cooking: A Simple Art; Japanese eel industry documentation