Unadon and Unaju: Grilled Eel Over Rice

Same glossy eel, same sweet-savory sauce, two ways to serve it, and a few small rules that make the meal better.

Published October 18, 2026 at 7:58 PM JST | By Tokyo Paul

Quick answer: Unadon is grilled eel brushed with a sweet soy glaze and laid over rice in a bowl. Unaju is the same dish served in a lacquered tiered box, usually with larger portions or a higher grade of eel. Both are traditionally eaten in summer, especially around the Day of the Ox in midsummer, and are best enjoyed hot, with sansho pepper.

What You Are Actually Ordering

Unadon and unaju are both built from kabayaki, the Japanese method of splitting an eel, skewering it, and grilling it while brushing on a sauce called tare. The sauce is a reduction of soy sauce, mirin and sugar, and in older shops it is said to be topped up and carried forward for years rather than made fresh each day. The result is a fillet that is soft inside, lightly charred outside, and glossy.

The difference between the two names is the container. Don means a bowl, so unadon is eel on rice in a bowl. Ju refers to jubako, the stacked lacquer boxes used for festive meals, so unaju arrives in a square box with a lid. Many restaurants treat unaju as the more formal choice and charge more for it.

The rice underneath is not plain. A little tare is usually worked into it or poured over it, so the lower layer tastes as good as the eel on top. Some places serve rice in one half of the box and eel in the other, while others lay a thin layer of eel between two layers of rice, a style associated with certain regions.

Grades, Sizes and the Matsu Take Ume Ladder

Many eel restaurants list their sets using the old three-step ranking of matsu (pine), take (bamboo) and ume (plum). Pine is usually the largest or most generous portion, plum the smallest. The names are only a ladder, not a quality guarantee, so the difference is typically the amount of eel, sometimes the number of fillet pieces, and not a different cut or cooking method.

If you are ordering for the first time, the middle step is a comfortable starting point. The smallest set can look modest on the tray but the eel is rich, and a standard serving is often enough for a satisfying lunch. Larger sets suit a hearty appetite or a shared meal with a side of grilled liver or a rolled omelet.

Some shops also list a version with extra rice or a double portion of eel. If you are unsure, the staff can usually point out which set is most popular. Check the menu board or the shop website for the current set names and prices, since both change from place to place and over time.

Kanto and Kansai: Two Ways to Cook an Eel

The two big regions of Japan treat the eel differently before it ever reaches the grill. In the Kanto area around Tokyo, the eel is traditionally split down the back, cooked first over charcoal without sauce, steamed to soften it, and then grilled again with tare. The steaming step gives a fluffy, melting texture that suits the sweet sauce.

In the Kansai area around Osaka, the eel is more often split along the belly and grilled directly over charcoal without steaming, which makes the skin crisper and the flesh a little firmer. The Kansai style can taste more robust and smoky. Neither approach is considered better; they are simply two regional answers to the same craft, and tasting both is a fun comparison.

These are broad tendencies, not strict rules, and individual shops follow their own method. If you are traveling between Tokyo and Osaka, eating eel in both cities makes a fun comparison. Regional specialties also exist elsewhere, including the Nagoya style served as hitsumabushi, where the eel is chopped, laid over rice, and eaten in several stages with garnishes and a broth.

Why Eel Is a Summer Tradition

The custom of eating eel in the hottest weeks is tied to a day called Doyo no Ushi no Hi, the Day of the Ox in midsummer. It falls in the late-July stretch of the old calendar, and many people eat eel around it for stamina in the heat. Shops often put out banners and extend their lines during this period.

A popular story links the habit to the Edo period, when an eel seller was said to have asked a famous scholar for help with slow summer sales, and the idea of eating eel on that day took hold. Whether or not the story is exact, the custom is firmly established, and the dish is welcome at any other time of year too.

Eel is rich in vitamins and oil, which fits the idea of a restorative summer meal. In practice, many people simply enjoy it as a special treat, with cold tea, pickles and a clear soup alongside. The point is more cultural than medical, and the dish is better thought of as a festive summer treat than as a remedy.

How to Eat It Properly

Eat the dish while it is hot, since the fat firms up as it cools and the flavor flattens. Use chopsticks to lift a piece of eel together with a bit of the rice beneath, so each bite gets both the savory sauce and the grain. The eel is tender enough to cut with the side of the chopsticks, and you do not need a knife.

Sansho, a citrusy and slightly numbing pepper, is usually set on the table in a small shaker. Sprinkle a little on the eel to cut richness; a pinch is enough because the flavor is strong. Some people also add a small amount of wasabi or sansho to the rice itself.

Lacquer boxes should be handled gently. Remove the lid, set it beside the box, and eat from the box without lifting it too high. Many shops serve a small bowl of clear soup with eel liver, called kimosui, which is worth trying if you enjoy a deeper, slightly bitter flavor.

Where to Find Good Eel Without Overspending

Specialist unagi restaurants exist in nearly every city, and many have been in the same family for generations. Look for places with a grill visible near the entrance and a smoky, sweet aroma outside. Since the eel is often cooked after you order, expect a wait of fifteen minutes or more; this is normal and part of the experience.

Department store restaurant floors and station buildings often include eel shops with set lunches at friendlier prices than stand-alone restaurants. Supermarkets and convenience stores sell packaged kabayaki that can be warmed at home and laid over rice, which is a modest way to try the flavor. Lunch sets in particular tend to be lighter on the budget, and the grilling smell drifting through a food hall is often the best advertisement.

Reservations are wise on the Day of the Ox and on weekends, when popular shops fill quickly. Check each restaurant's official site or local tourist information for current hours, closing days and menus before you travel. Some shops also sell takeaway boxes in those weeks, which can be a handy plan when the dining room has a long line.

Good Pairings and Common Mistakes

Eel pairs naturally with green tea, light beer, and dry sake. The oily richness is softened by a clean drink, and the pickles that arrive on the side are there to refresh your palate between bites. A simple cucumber salad or a vinegared dish also works well. A cold barley tea or a few slices of pickled cucumber also make good companions, since both clear the palate.

One common mistake is leaving the box or bowl to sit while the photos are taken. The eel is at its best in the first few minutes. Another is adding too much sansho at once, which can overpower the sauce, so start with a light dusting. If you plan to share a set, ask for extra bowls rather than passing the lacquer box around, which can damage the finish.

Visitors sometimes assume that unaju is always better than unadon. In many restaurants, the eel itself is the same and the difference is portion, presentation and price. If you simply want the flavor, either option works, and the bowl version is often the easier choice for a casual lunch. Ask the staff which set suits your appetite, and they will usually steer you to a sensible choice.

Frequently Asked Questions

Is unadon the same as unaju?

They share the same grilled eel and sauce, but they are served differently. Unadon comes in a bowl, while unaju comes in a lacquered box and is often offered in a more generous or formal set. The eel itself is usually identical, so the difference lies mostly in presentation, portion and price.

What does the sauce taste like?

The tare is sweet and savory, built from soy sauce, mirin and sugar. It is thick enough to cling to the eel and add a glossy sheen. It is not spicy, which makes the dish friendly for most palates, and the sansho pepper offers an optional citrus note.

Can you eat eel in winter?

Yes. Eel is eaten all year, and many restaurants serve it every day. Summer is the famous season because of the midsummer custom, but fans point out that eel can taste richer in colder months, so a winter meal is a perfectly good choice.

Keep Exploring

More guides from Tokyo Paul: Anago: Japan's Saltwater Eel, Oshizushi: Osaka's Pressed Box Sushi and Ayu: The Sweetfish of Japanese Summer Rivers.