What is "Doyo no Ushi no Hi" and Why Do People Eat Eel?

During the summer in Japan, many Japanese restaurants put up signs saying “Doyo no Ushi no Hi” to invite people to eat eel (unagi).
But what exactly does this phrase mean?

Understanding the Term

• Doyo refers to the 18-day period before the changing of each season. This period occurs four times a year, corresponding to spring, summer, autumn, and winter.
• Ushi no Hi means “Day of the Ox” according to the traditional Japanese zodiac, which rotates through the twelve zodiac animals.

So, Doyo no Ushi no Hi refers to the “Day of the Ox” that falls within the doyo period.

During doyo, it is believed that the Earth God, 土公神 (Dokōshin), resides in the soil. Therefore, it's considered inauspicious to disturb the earth by doing things like digging, farming, or construction.

Seasonal Food Customs During Doyo
For each doyo period, there are specific foods recommended based on two principles:

1. Eat foods that start with the same sound as the zodiac animal opposite the season’s sign.

2. Eat foods in colors opposite the element associated with the current season.

Here’s a breakdown:

• Spring Doyo (Day of the Dog - 戌): Eat foods starting with “I” (い) and white-colored foods.
• Summer Doyo (Day of the Ox - 丑): Eat foods starting with “U” (う) and black-colored foods.
• Autumn Doyo (Day of the Dragon - 辰): Eat foods starting with “Ta” (た) and blue-colored foods.
• Winter Doyo (Day of the Goat - 未): Eat foods starting with “Hi” (ひ) and red-colored foods.

Therefore, during the Doyo no Ushi no Hi in summer, Japanese people traditionally eat eel (unagi)—a food beginning with “U” and black in color.

Why Eat Eel?
Eel is not only a traditional and auspicious food, but it's also believed to restore energy and stamina during the hot summer months. It's rich in nutrients like collagen, omega-3, vitamin A and E—beneficial for boosting immunity and combating fatigue.
Though many cultures, including England, Italy, Belgium, Vietnam, and Thailand, eat eel, Japanese-style grilled eel glazed with sweet soy sauce is especially popular due to its tender texture and delicious flavor. Nowadays, you don’t even have to go to a restaurant—frozen pre-cooked eel is widely available for convenient home dining.

Not a Fan of Eel? No Problem!
If you don’t like eel or are allergic to it, you can still follow the “eat black foods on Doyo” tradition with other tasty options like:

• Black glutinous rice
• Black beans
• Grass jelly
• Shijimi clams
• Yokan (sweet bean jelly)
• Hijiki seaweed
• Eggplant
• Black sesame
  All of these can be found at Fuji Super!

Foods That Start With “U” (う)
Besides eel (unagi), there are many other foods that start with the character “U,” such as:

• Uri (melon)
• Uzura no tamago (quail eggs)
• And of course, Ushi! (beef)

Speaking of stamina-boosting foods, ushi (grilled beef) is perfect for summer. Imagine enjoying juicy grilled beef under the summer sky, with refreshing watermelon, marinated quail eggs, and crunchy pickled cucumbers—what a delicious way to enjoy the season.

Take this opportunity during Doyo no Ushi no Hi to treat yourself at UFM Fuji Super!