Japan — unagi consumption is documented from the Man'yōshū (8th century). The kabayaki preparation format developed through the Edo period; the Kantō style (with steaming step) became established in Tokyo's Yanagibashi eel restaurant district.
Unagi kabayaki (うなぎ蒲焼き) is the preparation of freshwater eel (unagi, Anguilla japonica) by splitting, cleaning, skewering, and grilling over charcoal with repeated brushings of sweet soy-based tare — a process that creates a lacquered, caramelised surface of extraordinary flavour and a rich, fatty interior. Unagi kabayaki is Japan's most celebrated summer food (土用の丑の日, Doyo no Ushi no Hi, the day of the ox in midsummer) and one of its most technically demanding preparations. The Kantō (Tokyo) method involves steaming the eel before the final grill; the Kansai (Osaka) method grills directly from raw without steaming.
Unagi kabayaki delivers one of Japanese cuisine's most profound flavour experiences: the tare's sweet-savoury caramelisation combines with the eel's extraordinary fat richness (unagi has among the highest fat content of any freshwater fish) to produce a deeply satisfying, opulent preparation. The steamed (Kantō) interior is almost custard-rich — the fat has partially rendered and the flesh becomes incredibly soft. The lacquered exterior provides Maillard caramelised contrast. On shari (sushi rice) or donburi rice, the combination is one of Japan's great comfort-luxury experiences.
The split-and-clean technique (saki-biraki): the eel is split from the back (Kantō) or belly (Kansai), the spine removed, and the fillet cut into manageable pieces. Skewered through metal skewers to prevent curling during grilling. Kantō process: first grilling (shiro-yaki, 白焼き, plain white grill) without tare, then steaming for 20 minutes to render fat and create a fluffy, tender texture, then final grilling with tare application in multiple rounds. Kansai process: direct grilling from raw without steaming — requires more precise heat management but produces a firmer, crispier result. Tare applications (usually 3–5 rounds of brush-and-grill) build the caramelised lacquer layer progressively.
The great unagi restaurants of Tokyo and Kyoto maintain tare pots that are decades old — each batch of new tare is added to the existing accumulated liquid, which carries the flavour history of thousands of eels grilled before. Some Tokyo unagi restaurants claim 100+ year tare lineages. The tare's evolution is not mythological — the accumulated eel fat, caramelised soy, and mirin develop a deep, complex character that fresh tare cannot replicate. The split-from-the-back Kantō tradition (vs belly split in Kansai) reflects a historical difference: the back-split was preferred in warrior culture (samurai avoided belly cuts as symbols of seppuku).
Grilling unsteamed eel at too-high temperature — the exterior caramelises before the interior renders. Insufficient tare layers — the lacquer requires multiple brush-and-caramelise cycles. Using commercial tare without development — unagi tare should be a living sauce, replenished with eel drippings over years. Serving on cold rice — the eel must be placed on freshly cooked, hot rice so the steam continues to warm the underside.
Japanese Cooking: A Simple Art — Shizuo Tsuji