Eel is one of the few Japanese foods that is genuinely difficult to approach from outside. It is expensive, it is seasonal in a way that has nothing to do with when the fish is actually good, it is never served raw for a reason most people have never heard, and the way it is cooked changes halfway down the country. Here is the whole picture.
Why eel is never served raw
Start with the fact that explains the most. Eel blood contains a protein toxin — an ichthyotoxin — that is genuinely harmful: it irritates mucous membranes, and in quantity it is dangerous. Eel processors have historically had problems with it getting into cuts and eyes.
The toxin is destroyed by heat. So eel is always cooked, without exception, and this is not a matter of taste or tradition. In a cuisine that eats almost everything else from the sea raw, eel sashimi does not exist because it cannot.
This also explains the grilling. Eel is not fried or simmered as a default; it is grilled over charcoal, repeatedly, with lacquering between passes. The heat is doing a job before it does anything else.
The two Japans of eel
Eel is the clearest example of the east–west split in Japanese cooking, and it runs deeper than a difference in sauce. Everything about the preparation diverges, and the dividing line sits around Hamamatsu in Shizuoka — which is, conveniently, also one of the country’s eel capitals.
| Kanto (Tokyo and east) | Kansai (Osaka and west) | |
| How it is opened | Split down the back | Split down the belly |
| Steaming | Steamed between grillings | Not steamed – grilled straight through |
| Head | Removed before grilling | Often left on until after |
| Result | Soft, fluffy, almost custardy | Crisp-skinned, chewier, more direct |
The explanation usually given for the back-versus-belly cut is cultural. Edo was a samurai city, where cutting open a belly carried an obvious and unwelcome association. Osaka was a merchant city, where the phrase for opening your belly meant speaking frankly and was a compliment. Whether that is the real historical cause or a story attached afterwards is not settled — but it is the explanation every eel restaurant in Japan will give you, and it is a good way to remember which is which.
The steaming is the bigger difference in practice. Steaming renders out fat and collapses the texture, which is why Tokyo eel can be eaten with chopsticks that barely close. Kansai eel resists slightly. People have strong opinions.
What to order
Kabayaki — the standard: butterflied, skewered, grilled, then repeatedly dipped in a sweet soy-mirin sauce and grilled again. The sauce barrel in an old shop is often decades old, topped up rather than replaced.
Shirayaki — grilled plain, no sauce. Eaten with salt, wasabi, or a little soy. This is the connoisseur’s order and the honest one: with no sauce to hide behind, you are tasting the eel and the grilling. If you want to know whether a shop is good, order this.
Unaju and unadon — kabayaki over rice. The only difference is the vessel: unaju comes in a lacquered box, unadon in a bowl. The box costs more and usually holds more eel, but it is the same dish.
Hitsumabushi — the Nagoya version, and the most interesting thing to order if you are having eel once. The eel is chopped and served over rice in a wooden tub, and it is eaten in stages. First quarter plain. Second with spring onion, wasabi and nori. Third with hot dashi or green tea poured over it as a kind of ochazuke. Fourth however you liked best. It is one dish that teaches you three preparations.
Kimosui — a clear soup with eel liver, which comes as standard alongside unaju in a proper shop. Faintly bitter, and the traditional counterweight to how rich the main dish is. Order it if it is not automatic.
U-maki — kabayaki rolled inside a Japanese omelette. Common as an izakaya dish and a good way to eat eel without paying eel prices.
The skin, incidentally, is eaten. It is grilled until it renders and is one of the better parts. There is nothing to remove.
Unagi day: why Japan eats eel in midsummer
Doyo no ushi no hi — the Day of the Ox in the doyo period — falls in late July, occasionally twice in one summer, and on it Japan eats an enormous quantity of eel. Supermarkets stack it, prices spike, and specialist shops queue out the door.
The reasoning given is that eel is rich and restorative and helps you survive the heat, which has some basis — eel is high in vitamin A and B vitamins. The wrinkle is that midsummer is not when wild eel is best. Wild eel is fattest in autumn and winter, as it prepares to migrate. Japan’s biggest eel day falls in the season when eel is at its worst.
The story usually told is that the eighteenth-century polymath Hiraga Gennai was asked by a struggling eel shop how to sell in summer, and told them to hang a sign saying it was the Day of the Ox — playing on an existing folk belief that foods beginning with the “u” sound were good for surviving the heat, and unagi begins with u. It is a good story. There is no contemporary evidence for it, and it appears in writing much later. Treat it as folklore that became a marketing tradition, which is more or less what it is.
Practically: if you want the best eel, go in late autumn. If you want the experience, go in July and accept the queue.
The uncomfortable part: eel is endangered
The Japanese eel, Anguilla japonica, has been listed as Endangered on the IUCN Red List since 2014. This is not a marginal concern attached to the dish; it is the central fact about its future.
The reason it is so hard to solve is the life cycle. Japanese eels spawn in the open Pacific, west of the Mariana Islands — a spawning ground that was not located until Japanese researchers pinpointed it in the 2000s, after decades of searching. The larvae drift thousands of kilometres on the currents to East Asia, where they arrive as transparent glass eels and are caught.
Nearly all “farmed” eel is therefore not farmed in the ordinary sense. Glass eels are caught wild and grown on in tanks. The farm is a fattening operation; the wild population still supplies every animal. Closing the cycle in captivity was achieved in a Japanese laboratory in 2010, but it remains far too costly and fragile to supply the market, and glass eel catches have been declining for decades.
The politics reached a head recently. At the CITES conference in late 2025, the European Union proposed listing all Anguilla species under Appendix II, which would have brought Japanese eel under international trade regulation. Japan opposed it, arguing the case for regulating all species on the grounds of visual similarity was not made. The proposal was rejected. European eel remains listed; Japanese eel does not.
So the position in 2026 is that eel remains endangered, remains legal to trade freely, and remains expensive and popular. If that sits uneasily, it should. Eating eel in Japan is not a neutral act, and the honest version of a guide to it says so. Shops that source from certified farms and that can tell you where their eel came from exist and are worth finding.
Where to eat it
Hamamatsu (Shizuoka) — the historic centre of eel farming, sitting on the Kanto–Kansai line, where you can eat both styles within a few streets.
Nagoya — for hitsumabushi, which originated there.
Yanagawa (Fukuoka) — for seiro-mushi, a local style where sauced rice and eel are steamed together in a basket and served with shredded egg. Distinct from both eastern and western preparations, and worth the detour.
Tokyo — for the old specialist shops, several of which have been grilling in the same room for well over a century. Expect to wait; eel is grilled to order and a proper shop will tell you it takes thirty to forty minutes.
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