If you happen to find yourself in a Japanese supermarket on July 30th this year (2023), you might be in for a slippery shock. In nearly every supermarket in the country you’ll find huge displays of delicious grilled freshwater eel slathered in sweet and savory sauce on sale for Doyo no Ushi no Hi, one of Japan’s many food related pseudo-holidays. Join us as we break down what Doyo no Ushi no Hi means, its fascinating origin, and some tips for making your own grilled eel, as well as some vegan alternatives. 

What’s in a name? 

 

So what exactly is Doyo no Ushi no Hi (土用の丑の日)?

Let’s break down the Japanese! 

• Doyo (土用): a period of 18 days before the beginning of seasons in the traditional Japanese solar calendar. This holiday specifically refers to the summer Doyo (July 20th - August 7th, for 2023.)
  
  
• Ushi no Hi (丑の日): Literally “Day of the Ox.” In this case, it's from the Chinese Zodiac (which is pretty commonly used and referenced throughout Japan as well.) Every day has a corresponding zodiac sign. 
  

Okay, so we’ve sorted out the name, Doyo no Ushi no Hi is the day of the ox that occurs during the Doyo period! Wait back up a bit… what on earth does “day of the Ox” have to do with eating grilled eel? Shouldn’t we be having sales on steaks instead? Good question, and the answer is a bit simpler than you might expect. I’ll give you a hint: the Japanese word for eel is “unagi.”

 

A Little Alliteration Goes a Long Way

 

Legend has it that during the Edo period an eel restaurant owner was having a rough time with sales in the heat of summer, as grilled eel was a hearty dish that sold better in winter. The distraught owner turned to his friend, the famous samurai scholar Hiraga Gennai for advice. 

His advice was to use a bit of alliteration and wordplay, drawing up a sign that read “Unagi for Ushi no Hi.” 

This played on one of the common beliefs of the age; foods starting with “u” are healthy and revitalizing, a necessity to combat fatigue stemming from the unforgiving heat of Japanese summers. This was backed up by the fact that unagi is quite healthy and hearty, boasting plenty of vitamins A and E, as well as protein and omega-3s. Combined with Gennai’s reputation as a respected physician and scholar of the time, the sign worked brilliantly, saving his friend's store and, unbeknownst to him, starting a new summertime tradition. 

Gennai’s marketing mastery and wondrous wordplay proved to be wildly successful, leading to other eel stores and restaurants running similar sales on Doyo no Ushi no Hi, a tradition that’s continued into the modern era.

Doyo no Ushi no Hi in Modern Japan

In modern day Japan, unagi has remained a quintessential summer food, as it’s delicious and incredibly simple because most unagi comes pre-cooked, and even pre-sauced. On Doyo no Ushi no Hi supermarkets and restaurants offer deep discounts on unagi, making it the perfect time to indulge. The most common way of eating it is Unaju: grilled eel served on a bed of rice, served in a beautiful rectangular lacquer box, called jubako (una meaning eel, ju coming from jubako.) Jubako are typically red on the inside, and a rich dark brown on the outside, matching the grilled and caramelized eel filets resting inside. 

Tips on making your own Unaju and Alternatives

While cooking unagi is generally quite straightforward (broil, add sauce, put on rice, enjoy) here’s some tips if you’re f-eeling a little lost. 

• Is the Price Right?: You might be shocked to see some eels going for 2-3 times as much as others; this is typically due to origin. Eels raised domestically in Japan are considered top quality and are considerably more expensive than eels from China and other Asian countries.
  
  
• Broiled, not Baked: In order to get a nice crispy caramelized finish on your unagi, broil it on aluminum foil for 5-6 minutes instead of baking it. If you go for the traditional grilled approach, make sure your coals are nice and hot before slapping your filets on the grill.
  
  
• Sauce it Up!: Even if your store bought unagi has some sauce on it, don’t be afraid to make your own sauce and slather on multiple layers as you broil it. It’ll help you get that nice caramelized finish.
  
  
• I don’t Eel so Good, Doc: In recent years, eel-free variants have gained popularity as well. Whether it’s due to price, taste, dietary restrictions, sustainability concerns, or personal preferences, here’s some tasty alternatives to try out:
• Catfish (recipe by Just One Cookbook) - readily available, and much cheaper than authentic unagi filets. Just make sure to get thin cuts!
  
  
• Eggplant (recipe by No Recipes) - right out of the box- er, field, eggplant has a very similar shape and texture to unagi filets. Marc Matsumoto recommends lots of small slits across the eggplant, giving you tons of surface area to soak up that succulent sauce.
  
  
• Tofu - a staple in vegetarian and vegan cuisine, mashed tofu with cornstarch or potato to hold it together makes excellent faux eel, for real.

Seal the Eel with a Proper Box

One of the most important aspects of Japanese cooking is presentation. For unaju, this is particularly important as using a plain old bowl turns it into a different dish entirely: unadon. If you’re looking to get your hands on an authentic jubako for your unagi, look no further than our Unagi Bento Box. Made in Japan from BPA-free plastic, it’s the perfect container to serve your unaju, as well as other home cooked meals in. It’s also dishwasher safe, making cleaning up those last bits of sauce a breeze. 

View the Unagi Bento Box ($18.00 USD)

 

Like many other food-based holidays around the world, Doyo no Ushi no Hi started with some clever marketing, but has grown into a popular summer tradition. From the alignment of zodiac signs to the sizzling eel feasts, Doyo Ushi no Hi offers a fascinating glimpse into the cultural and culinary history of Japan.We hope you’re f-eel-ing inspired to give this deceptively simple yet delectable dish a try!