Around July in Japan, you’ll start seeing ads for unagi (freshwater eel) everywhere. This is because of a special holiday called doyo no ushi no hi or “midsummer day of the ox” in English—a day in mid-July to celebrate the transitional period between spring and summer.
To celebrate, people eat unagi, thought to be filled with healthy vitamins and nutrients to enhance their stamina so they can get through Japan’s hot summer days. Typical dishes include unagi kabayaki, skewered and cooked over charcoal, then dipped in a sweet sticky sauce and unaju (broiled eel on rice).
It’s a long-honored tradition in Japan—despite sustainability concerns and a depleting population. But what’s the story behind eating eel, and what does it have to do with ushi (ox)?
What is ox day?
Doyo no ushi no hi comes from Daoism, a school of philosophy from China. In both Chinese and Japanese, dao means “the way.” Simply put, Daoism emphasizes that everything in nature follows a pattern that helps explain the world around us and how to predict future occurrences. This belief includes designating meaning to different dates, times and directions or feng shui.
Daoism is related to the Chinese zodiac, which makes up the 12-year cycle that gives each year an animal name, starting with the rat and ending with the boar. Within the cycle is the ox, the second sign in the Chinese zodiac and doyo, which acts as the signifier for the last 19 days before the change in season. It just so happens that the day of the ox happens during the doyo period, thus doyo no ushi no hi. While it sounds like a pretty long-winded connection, it, along with tradition, is why people eat unagi in July.
Why eat unagi on ox day?
Good marketing. No. Seriously. While there are a few tales about why unagi is popular in summer, the most famous story involves the Edo period genius and samurai Hiraga Gennai. The story goes that Gennai had a friend with an unagi shop who lamented that the barbecued unagi business was great in cold weather but awful in summer.
At the time, and even today, people in Japan believed that foods beginning with the “u” provided the health and stamina to get through Japan’s unbearable summers. It isn’t known where this custom started, but people ate a lot of foods like ume (Japanese plum) and udon (thick wheat noodles) to beat the heat. However, for whatever reason, unagi wasn’t favored in summer.
With this in mind, Hiraga Gennai simply connected the “U in unagi with the “U” in ushi. He made a sign for his restaurant friend that read, “Grilled Eel on the Day of the Ox,” and the people ate it up—literally! Hiraga, being a famous polymath samurai, was a pretty smart guy. People assumed he knew his stuff. Afterward, the trend grew, and other unagi shops began to emulate it.
Unagi Sustainability and alternatives
There is concern over overfishing and the sustainability of the freshwater eel population. Japan consumes an estimated 70% of the freshwater eel catch despite The Japanese Ministry of the Environment listing it as endangered.
If you’re in Japan and want to partake in the Edo-summer tradition without feeling guilty, an alternative is anago (saltwater eel). It’s a milder, less fishy-tasting substitute. It doesn’t start with “U,” but that only means you can eat it anytime!
