Unagi Explained: The Tradition Behind Eel in Japan

Unagi is one of the most widely celebrated and comforting ingredients in Japanese cuisine. Harvested mainly from rivers and estuaries in the colder months when the meat turns tender and rich–or during the summer for farmed eels–it is a seasonal favorite often enjoyed in the hotter season.

This eel’s bold yet balanced flavor of smokiness, sweetness, and savory has earned it a place in Japan’s culinary tradition for centuries!

What is unagi?

Unagi is the Japanese word for freshwater eel (Anguilla japonica), a delicacy often enjoyed grilled over charcoal and brushed with a soy-based sauce called tare. It has a natural sweetness, balanced by the smoky char from the grill and the glossy tare sauce. The meat is also soft yet slightly firm, with a texture that melts in your mouth, and the sauce adds layers of umami and a sweet soy sauce flavor. 

In Japanese cuisine, unagi is celebrated as a food that provides strength and vitality, especially during the humid summer months. Traditionally, it’s eaten on a day called Doyō no Ushi no Hi, or Midsummer Day of the Ox.

People also believe that eating unagi helps restore energy lost to the heat, and this custom continues to this day. Interestingly, this custom is said to have been devised by Hiraga Gennai, a scholar of the Edo period (1603-1868), as a marketing strategy for restaurants serving eel.

A Short History of Eel in Japan

Unagi has been part of Japan’s food culture for over a thousand years. During the Edo period, it gained particular popularity in Tokyo, where rivers were teeming with eels. Vendors would grill them over open fires, and the scent of sizzling unagi would drift through the streets, drawing in customers.

The dish evolved from simple grilled eel to the refined kabayaki style we know today. They’re filleted, skewered, grilled, steamed, and then glazed with tare sauce. Each region in Japan even developed its own take! Kansai-style (Osaka) unagi cuts the eel along the belly and skips the steaming step, resulting in a crispier and savory texture. On the other hand, Kanto-style (Tokyo) unagi is cut along the back and steamed before grilling, making it tender and delicate.

This difference in preparation is due to regional cultural and religious beliefs. Kanto carries a samurai background, and the idea of cutting from the stomach was too similar to seppuku, a method of self-inflicting death used by samurai to die with honor. Thus, they believed that doing so would bring bad fortune to the food.

However, nobility and merchants had a significant influence on Kansai, in contrast. They had no qualms with slicing along the belly, which is a more straightforward process. Such is a riveting example of how beliefs can seep into even the most basic aspects of food and culinary methods.

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How to Prepare Unagi

Fresh unagi must first be filleted and cleaned carefully. This step is where precision matters most, as eels have tough skin and many delicate bones. To prepare unagi properly, Japanese chefs use a specialized knife called the unagisaki. It’s a type of single-bevel knife explicitly designed for filleting eel. 

Each region of Japan also has its own variation of the unagisaki due to differences in preparation! The Kanto-style unagisaki has a sharp triangular blade, while the Kansai-style version has a pointed tip. Both are forged with high-carbon steel, ensuring precision and control—two things essential for working with eel.

Once the eel is filleted, it’s grilled lightly over charcoal to firm up the meat and remove excess fat. It is then steamed or boiled, depending on regional style. Once the desired texture has been achieved, unagi is basted with tare, which is made from soy sauce, sugar, sake, and mirin as the unagi is repeatedly brushed and grilled. Finally, the sauce caramelizes, forming a glossy layer that enhances its smoky sweetness.

Dishes You Can Make with Eel at Home

With proper preparation and caution, you can enjoy delicious unagi in the comfort of your own kitchen. Many Japanese markets sell pre-grilled or vacuum-sealed eel, which makes cooking much simpler. Here are three dishes that bring out the best of this flavorful ingredient:

Unadon (Grilled Eel Rice Bowl)

This is the most iconic unagi dish. Slices of grilled eel are laid over warm white rice and drizzled with extra tare sauce. Its simplicity is perfect for showcasing the natural richness of the eel. To serve, sprinkle a bit of sanshō (Japanese pepper) for a citrusy, peppery kick.

Hitsumabushi (Nagoya-style Unagi)

Hitsumabushi is a fun, interactive way to enjoy unagi. The eel is chopped into bite-sized pieces and served over rice in a wooden bowl. You first eat it plain to savor its innate flavors, then mix in condiments like green onions, seaweed, and wasabi. Finally, you pour hot broth or tea over the rice for a comforting, soupy finish.

Unagi Sushi

Unagi sushi is a favorite for those who love a blend of textures. The eel is typically served grilled and slightly warm, resting over a bed of seasoned sushi rice. A glossy brush of tare sauce adds that irresistible sweet-salty flavor that defines unagi.

Why try cooking with unagi?

Cooking with unagi at home is a great way to understand Japanese cuisine and its techniques in depth. Unlike many other fish, eel transforms when grilled. The fat caramelizes, the sauce thickens, and the aroma fills the kitchen with warmth. 

Using the unagisaki knife adds another layer of authenticity. It gives you a deeper appreciation for the skill Japanese chefs bring to the table, as well as the craftsmanship that goes into Japan’s cooking tools. Learning to handle such a specialized tool helps refine your knife skills across all types of cuisine!

And of course, there’s the taste. Few dishes feel as satisfying or as memorable as unagi. It’s rich but balanced, luxurious yet comforting. Reward yourself with such a meal after a long, hard day of work. Have you ever tried unagi before? How did you like it? Let us know in the comments!