The Complete Guide to Unagi: Japanese Freshwater Eel

Japan is well known for many dishes, including ramen, soba, tempura, and sushi. But have you ever heard of unagi? This comprehensive guide will take you through the fascinating world of unagi, covering everything you need to know about this mouthwatering dish.

Check out our list of 50 traditional Japanese foods to try for more food inspiration.

Unagi refers to freshwater eel, specifically the species Anguilla japonica. Unagi is typically prepared by grilling it over charcoal and glazing it with a savory sauce. It's known for its firm but tender flesh, indulgent fattiness, and distinctively sweet flavor. 

While unagi is available all year, it's especially popular during summer. Some believe that eating unagi boosts stamina and heat tolerance during the humid and hot Japanese summers.

Unagi is often confused with anago, another type of eel commonly found in Japanese cuisine. While both eels belong to the same family, they have distinct differences. Unagi is a freshwater eel, while anago grow up in salt water. Unagi has a much higher fat content, resulting in a richer, buttery flavor. Anago, on the other hand, has a lean, fluffy texture and milder taste. Both types of eel have their unique appeal and are eaten in various ways, but unagi has traditionally remained the more popular choice.

Unagi is prepared and enjoyed in different styles across Japan. The most prominent variations are Kanto style and Kansai style. Kanto-style unagi is typically fileted, skewered, and grilled. Then, it's steamed before being grilled again and finally brushed with a sweet soy-based sauce. Kansai-style unagi is butterflied and then grilled in sauce. No steaming is involved, resulting in a crispier exterior and softer interior.

One of the most popular ways to enjoy unagi is over freshly steamed white rice. When the grilled eel is placed in a bowl, it's called unadon. When it is placed on rice in a lacquered box, it's known as unaju. 

You'll also find unagi in sushi rolls, fried tempura style, and even in hot pots. Umaki is another dish where the grilled eel is wrapped in egg. There's also uzaku, where the eel is cut into small chunks and mixed with cucumber and a vinegar-based sauce to make a light, refreshing side dish.

Unagi sauce, also known as kabayaki sauce, is an integral component of the unagi experience. The sauce is made by simmering soy sauce, mirin (a sweet rice wine), sugar, and sometimes sake together until it thickens into a glossy, caramel-like consistency. The resulting sauce perfectly complements the natural flavors of the unagi, adding depth and richness to the grilled eel.

Making your own unagi sauce at home is quite easy. To make kabayaki sauce:

1. Combine 1 cup of soy sauce, 1 cup of mirin, 1/2 cup of sugar, and 1/4 cup of sake in a saucepan.
2. Bring the mixture to a boil, then reduce the heat and simmer until it thickens to the desired consistency, stirring occasionally.
3. Once the sauce has cooled, glaze your grilled unagi or use as a dipping sauce for various dishes.

Unagi restaurants can be found throughout Japan. In Tokyo, the Nihonbashi neighborhood is known for its long-standing unagi restaurants. Kyoto also boasts exceptional establishments, especially in the Pontocho district, where you can enjoy Kansai-style unagi. Otherwise, consider visiting Nagoya, which is famous for unagi. 

If you're looking to savor authentic unagi, there are a multitude of renowned restaurants that specialize in this delectable dish. Here is a list of famous unagi restaurants:

1. Sumiyaki Unafuji Daimaru Kyoto Bettei (Kyoto): A Michelin-featured unagi restaurant in Kyoto, Unafuji is led by Chef Mizuno, who honed his craft at multiple unagi establishments over two decades before making his mark at Unafuji — now a name with multiple branches. The restaurant is renowned for its extra-large, fatty “blue eel”, prepared in the Kansai style. Grilled over a 1,000°C charcoal fire, the eel develops a beautifully crisp crust while sealing in its rich, buttery flavor.

2. Unag Kappo Oedo (Tokyo): With an unorthodox marination method and a 200-year-old secret sauce recipe, Unagi Kappo Oedo has been keeping loyal patrons for generations. Rather than brushing the sauce onto the eel, the chefs fully immerse each piece into the jar, allowing the flavors to penetrate deeply. This process mirrors the concept of a perpetual stew — a continuously evolving sauce that gains complexity over time.

You can also find some of the best unagi restaurants in Tokyo.

Declines in the wild eel population and, as such, the rising cost of eel have made unagi more of a luxury treat than a meal for daily consumption. Concerns about overfishing, habitat loss, and pollution have all contributed to concerns about the sustainability of unagi. 

In 2013, Japan added unagi to its endangered species list. Efforts are being made to promote more sustainable practices to ensure the long-term viability of eel consumption, but consumers should be aware that no major breakthroughs have been found. 

If you're curious to try unagi but wish to be mindful and support sustainable practices, look for restaurants that source their unagi from responsibly managed farms and sustainable aquaculture practices. 

For those following a vegan or vegetarian lifestyle, several alternatives are available to experience the flavors and textures of unagi. Several plant-based options have been developed using ingredients such as tofu, eggplant, or mushrooms, which are marinated and grilled to mimic the taste and appearance of unagi. Be sure to look for these on the menus of vegan and vegetarian restaurants in Tokyo and Kyoto.

Unagi is a dish that combines tradition, cooking mastery, and exceptional flavors. Whether you're a seasoned food lover or a curious explorer of new tastes, this Japanese delicacy promises a remarkable dining experience. Add a stop at an unagi restaurant to your next Japan itinerary. 

Want to learn more about Japanese food? Check out these delicious guides:

• What is Mochi
• What is Wasabi
• Types of Sushi