What is Unagi (Freshwater Eel) ? (2023)

You will like unagi in your sushi rolls or perhaps as a part of your omakase course. Or, maybe you just like to eat white rice with eel sauce (if you haven’t, it’s a game changer, try it). No matter what form, or what you call it whether “unagi” or “eel”, it’s a fatty, meaty and delicious sushi and a much-loved staple of Japanese food enthusiasts around the world. So what is unagi, anyway? It seems like it should be seafood, because it is often listed on the sushi menu, but is it something you can catch on your next fishing trip? Is there other ways to eat unagi? Let’s find out more about this popular food!


  • What is Unagi?
  • The History of Unagi
  • Nutrition
  • Unagi Sushi
  • Let’s Cook Unagi (Eel) Sauce at Home (Unagi Sauce Recipe)
  • Nijiya Specialty Unagi Kabayaki (Broiled Eel)
  • How to Cook Unagi? (Eel Recipe)

What is Unagi?

What is Unagi (Freshwater Eel) ? (1)Unagi is the Japanese word for freshwater eel. If you haven’t seen them in their natural habitat, eels live in rivers and lakes, and migrate to the ocean to spawn. They are snake-like in shape and are about two feet long. Is it easy to cook? Let’s just say, in Japan, chefs dedicate their entire lives to learn the highly specialized skill of cooking unagi. How is it eaten? In Japan, surprisingly, sushi is not the preferred way to eat unagi. The most common way is going to an unagi restaurant and ordering a “unaju” or “unadon”- grilled unagi over rice with eel sauce topped with sprinkles ofsansho powder. With that, you are eating a big fillet of unagi. How is it prepared? First, unagi is dipped in eel sauce as it is grilled over charcoal to achieve the perfect fatty bite. This process will be repeated several times so the unagi can soak up the eel sauce and caramelize its surface. Then it’s placed over steamed rice, where the rice absorbs part of the sauce from the dripping fat. If you are a true unagi lover, this is a must-have dish. Other popular ways to eat unagi in Japan are the unagi omlette (‘umaki’), chopped grilled unagi over rice (‘hitsuma bushi‘), a side dish salad (‘uzaku’), and for maximum enjoyment of unagi flavor and texture, ‘shirayaki’, eel grilled without the signature sauce, which is often eaten with wasabi. In America, unagi is eaten mostly as sushi. When Japanese restaurateurs started serving unagi in the States, they noticed that people were not keen on its slightly slimy skin or how it looked, but eel sauce proved popular with customers. So, they thought serving it in a smaller size, perhaps with a sushi roll could work, and it did! With the current popularity of sushi and unagi, many Japanese restaurants outside of Japan have started to offer ‘unaju’ and ‘umaki’.

The History of Unagi

What is Unagi (Freshwater Eel) ? (2)Although eel bone remains have been found in shells dating to 5000 years ago, consuming eel didn’t become part of the Japanese diet until much later. The very first mention of unagi consumption in the public record is inManyoshu, the oldest Japanese poetry collection from the 8th century. Other records mention that late 8th century Japanese royalty ate steamed unagi. Eating unagi with sweet unagi sauce, as we are accustomed to now, came much, much later in the 18th century when dark soy sauce had become popular in Edo (current Tokyo). Until then, unagi was eaten just like any other fish: grilled or steamed and seasoned lightly with salt.


What is Unagi (Freshwater Eel) ? (3)Japanese people consider unagi to be one of the most nutritious fishes. So much so, every July, when the hot and humid summer starts in Japan and people start to become exhausted from the heat, unagi restaurants, fish markets, and grocery stores all start promoting “unagi day” (‘doyo no ushi no hi’) to encourage people to eat more unagi. Why? It started as a marketing tactic in the 18th century but it has become common knowledge for Japanese people that eating unagi can give a person a healthy energy boost. Is it true? Unagi is packed with vitamin A, B-complex, D and E that fights fatigue and loss of appetite. At the same time, the smell of cooking unagi over the grill itself is an appetizing smell for Japanese people. Another benefit? Unagi may make you smarter and more beautiful. A scientific study showed that unagi provides high levels of omega-3 fatty acids, DHA and EPA. DHA is considered to be great for the human brain and for youthful skin, and EPA can lower inflammation and prevent blood vessel disease. So not only is it delicious, but unagi sounds like a pretty healthy food, too.

Unagi Sushi

What is Unagi (Freshwater Eel) ? (4)Do you prefer unagi sushi as a roll or a nigiri? According to our survey, “10 Best Nigiri Sushi Menu”, unagi sushi ranks 5th among American sushi fans. That sweet and salty eel sauce on grilled fish is ‘gateway sushi’ for raw-fish phobes. It masks the fear of eating something new, because it is similar to something people are already accustomed to, teriyaki sauce. Therefore, unagi gives familiarity and comfort to sushi beginners. Some of the high-end sushi bars serve your unagi sushi nigiri with peppery sprinkles. The chef mentions that “It’s sansho peppers.” You nod and pretend to understand what he just said, but inside, you ask yourself, “What? What is san… what?” Next time, remember this: sansho is a Japanese aromatic pepper, which gives a little heat to dishes. Because eels are freshwater fish, sometimes they can have a unique earth like smell. So the pepperiness and the aroma of sansho powder gives unagi a little punctuation. It also cuts the fattiness of meat. Also sansho is known to help digestion, according to eastern medicine.

The most popular unagi sushi in America is probably the caterpillar roll: unagi and cucumber on the inside, avocado on the outside, and drizzled with eel sauce on top. It’s difficult to point out the origin of this delicious roll, but it has certainly become a classic. Equally popular is eel sauce itself. Even if there’s no eel on or in the sushi roll, many rolls are finished with a drizzle of eel sauce. In addition, it works especially well with tempura based rolls.

If you want to eat unagi sushi like Japanese people do, try a futomaki. It is a traditional Japanese sushi roll that contains unagi with spinach, egg, and cucumbers. There are no raw ingredients in it, so it is a popular take-out item that goes well with a touch of soy sauce. Since futomaki is not widely known in America, ask the sushi chef if he can make one for you. Most chefs probably will, since they usually have most of ingredients on hand. Just make sure you have a room in your stomach. Futomaki literally means “fat roll,” so as you can imagine, it is pretty filling.

Let’s Cook Unagi (Eel) Sauce at Home (Unagi Sauce Recipe)

What is Unagi (Freshwater Eel) ? (5)
Have you ever asked for extra eel sauce at the sushi bar? Without eel sauce, a sushi roll is just not as good, and simply put, without its sauce unagi is incomplete. It’s sweet and salty, highly addictive and makes everything taste better. Think of it as soy sauce on steroids. In Japan, some restaurants’ eel sauces are kept over years, with only additions to the mother sauce added to keep the flavor going. At long established restaurants, recipes are kept in the family for generations, but, with a few simple ingredients, you can start your own family recipe. But, in our busy world, why should you make your own, when you could just buy it at the store? Because it’s easy! Plus most of the store bought sauces tend to be either too salty or too sweet, and filled with preservatives. Try it as a replacement for soy sauce when you stir fry vegetables, grill tofu, or cook any protein or on tempura. Plus, it doesn’t just spice up Asian cuisine, try it on your next burger or mix it with some mayonnaise to make a great dipping sauce or salad dressing.
Below is a basic, fool proof recipe for eel sauce. Enjoy!

Unagi (Eel) Sauce Recipe

What is Unagi (Freshwater Eel) ? (6)

Ingredients (Serves cup 2)

  • Soy sauce 1/2 cup
  • Mirin (sweet sake) 1/2 cup
  • Sake 1/4 cup+
  • Brown sugar 1/4 cup+

Cooking Directions

  1. In a small sauce pan, pour mirin and sake, cook over high heat until it boils, then turn down to medium heat.
  2. Stir with a spatula until the smell of alcohol disappears (about 2-3 minutes).
  3. Turn down to low heat and add brown sugar. Keep stirring until the sugar dissolves.
  4. Add soy sauce. Soy sauce and sugar tend to burn quickly, so avoid burning by stirring constantly.
  5. After 10 minutes, taste the sauce. if you prefer it sweeter, add more sugar about 2 Tbsp at a time. If you like it less sweet, add 1 Tbsp of soy sauce and 1/2 Tbsp of sake. Keep stirring until the sauce thickens, and look for a maple syrup texture.
  6. Once it reaches your desired texture and sweetness, wait for it to cool down. The sauce will thicken more as it cools down. Pour it into an air tight jar. You can keep it in up to 2 weeks in the fridge.


  • If you want to develop a little bit more umami in the sauce, add 2-3 tsp of dashi powder when you add sugar. If you are feeling more adventurous, and have access to real unagi, cook the unagi bones and the head with sake and mirin. Remove them before adding soy sauce and strain the sauce with a cheese cloth, then add soy sauce and it put back on the stove.
  • You can substitute the brown sugar with honey, agave or maple syrup, but you may need more to achieve the desired sweetness. Artificial sweeteners are not recommended, as they do not give the proper thickness to the sauce and leave a bitter aftertaste.
  • Do not attempt to use your sauce as a mother sauce, as more work is required to kill bacteria. Many restaurants keep cooking the sauce every day to avoid this problem. Without the proper skills, it can be more dangerous than mouthwatering.

Nijiya Specialty Unagi kabayaki (Broiled Eel)

Full-scale charcoal fire eel kabayaki with no chemical additives

What is Unagi (Freshwater Eel) ? (7)This is a healthy eel dish using special sauce without any chemical additives. Nijiya’s eel kabayaki is manufactured at a designated factory in China’s Guangdong Province using the latest health maintenance system. Nijiya strictly controls the quality of the raw ingredients and the grilling technique through frequent communication with the producer.

The use of charcoal in grilling imparts a savory aroma and keeps the flesh plump and juicy. This is a kabayaki for connoisseurs. Production is entirely made to order so that only fresh eels are delivered to Nijiya Market. A safe and secure specialty product, Nijiya’s eel kabayaki is a highly recommended food for connoisseurs.

Kagoshima-made charcoal eel kabayaki

What is Unagi (Freshwater Eel) ? (8)Kagoshima is currently the largest producer of eels shipped in Japan. Among their eel kabayaki products is a kabayaki grilled with a special sauce and using Binchotan charcoal. The method of slow grilling over high heat imparts a savory aroma to the eel. The surface is crispy and flavorful while the inside is plump and juicy. The special quality of Kagoshimamade charcoal eel kabayaki is experienced at first bite.

How Best to Prepare Unagi

To use a grill or a frying pan, remove the eel from the pack, place it on aluminum foil skin side down, and warm it over a low flame. To enhance the aroma, you can coat the eel with the sauce during heating. The eel is ready to eat when the savory aroma begins to emerge as the flesh turns plump.

To heat in a microwave oven, remove the eel from the pack and place it in a heat-resistant dish. Sprinkle about a teaspoon of Japanese sake or cooking sake and cover with plastic wrap before heating. The sake makes the flesh more plump. As a rule of thumb, heat for about two minutes at 500w but please watch carefully and adjust accordingly as the outcome may vary depending on the model of your microwave.

A large quantity of carefully selected, delicious eel is delivered at Nijiya Market every year. Please be sure to enjoy Nijiya specialty eel as a way to survive those hot summer days.

How to Cook Unagi? (Eel Recipe)

Umaki (dashimaki tamago with eel) Recipe

What is Unagi (Freshwater Eel) ? (9)

Ingredients (Serves 2)

  • 2 eggs
  • 2 Tbsp. dashi
  • 2 tsp. brown sugar
  • 1/2 tsp. soy sauce
  • 1/2 fillet unagi kabayaki (already cooked and packed)
  • White sesame oil
  • 1/2 tsp. sansho powder, as desired

Cooking Directions

    What is Unagi (Freshwater Eel) ? (10)
  1. Cut unagi kabayaki into the same width as a square fry pan. Sprinkle sansho powder over the unagi if you like.
  2. In a medium sized bowl, whisk eggs with dashi, sugar and soy sauce. The surface of the egg mixture should not be very foamy.
  3. What is Unagi (Freshwater Eel) ? (11)

  4. Heat 2 teaspoons of oil in the pan over medium heat. When a pan gets moderately hot, pour a half of egg mixture into the pan. Before the egg mixture is thoroughly cooked, lay the unagi on the mixture and roll. Make the unagi come to the center of roll. Oil the pan again with 1/2 teaspoon of oil, pour the rest of the egg mixture into the pan and roll.
  5. Cut the omelet into one inch pieces. Place those pieces on a serving plate with the sections of omelet up.

Recipe and photos by: Yasuko Muro

Gochiso Magazine, Nijiya Market

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