Doyo no Ushi no Hi: Japan’s Delicious Day of the Ox
If you have ever visited Japan in late July, you are intimately familiar with the oppressive humidity that blankets the archipelago. The air feels heavy, energy levels drop, and the appetite often vanishes. The Japanese have a specific word for this summer fatigue: natsubate. However, centuries of tradition have provided a delicious culinary antidote.
Enter Doyo no Ushi no Hi, or the “Midsummer Day of the Ox.” On this specific day, the scent of charcoal smoke and sweet soy sauce fills the streets, as millions of people partake in the ritual of eating unagi (freshwater eel) to regain their strength.
The Origins of the Calendar
To understand the Day of the Ox, one must look back to the ancient timekeeping systems imported from China. Historically, Japan used the Twelve Earthly Branches (the Chinese Zodiac) not just for years, but also to label days. The Ox (Ushi) is the second animal in this cycle.
“Doyo” refers to the 18-day period leading up to the change of seasons. While there is technically a Doyo period for spring, autumn, and winter, the summer Doyo is the most significant because of the intense heat leading up to Risshu (the start of autumn). Therefore, Doyo no Ushi no Hi occurs when the day of the Ox falls within this pre-autumn period. Because the cycle of days shifts annually, the date changes every year, usually landing between July 19th and August 7th.
The Legend of Hiraga Gennai
Why eel? While freshwater eel is nutritious and rich in Vitamin B1—perfect for combating heat exhaustion—the connection between the Day of the Ox and eel is widely attributed to one of Japan’s first marketing geniuses.
The most popular origin story dates back to the Edo period (1603–1867). An eel restaurant owner was struggling to sell his heavy, rich food during the hot summer months when business usually slumped. Desperate, he consulted Hiraga Gennai, a famous inventor, pharmacist, and rangaku (Western studies) scholar.
Gennai drew upon a piece of folk wisdom stating that eating foods beginning with the sound “U” would provide stamina on the Day of the Ox (Ushi no Hi). He advised the owner to post a sign saying, “Today is the Day of the Ox.”
The sign was a hit. The novelty combined with the “U” superstition (foods like umeboshi plums and udon noodles were also contenders) created a frenzy. The restaurant flourished, and other shops quickly copied the tactic. Thus, what might have been the world’s first viral marketing campaign cemented a permanent national tradition.
Modern Culture and Conservation
Today, the tradition is less about superstition and more about culinary appreciation and seasonal endurance. Walk into any Japanese supermarket in late July, and you will see dedicated displays of grilled eel fillets, or kabayaki, glazed in a savory tare sauce.
However, modern culture faces a dilemma. The Japanese eel (Anguilla japonica) has become an endangered species due to overfishing and habitat loss. This has driven prices up significantly, transforming unagi from a common meal into a luxury.
In response, culinary innovation has stepped in. “Unagi-style” alternatives made from catfish, pork, or even fish paste shaped like eel have become popular for budget-conscious diners who still want to participate in the spirit of the holiday without the high cost or environmental impact.
Traveler’s Tips: How to Participate
If you find yourself in Japan during the Day of the Ox, here is how to enjoy the experience like a local:
1. Plan Ahead
Famous eel restaurants, particularly in older districts like Narita or older parts of Tokyo, will have lines stretching down the block. Many high-end establishments require reservations weeks in advance for this specific day.
2. Know Your Styles
There is a regional difference in preparation. In Kanto (Tokyo area), the eel is steamed before grilling, resulting in a fluffy, tender texture. In Kansai (Osaka area), the eel is grilled directly without steaming, creating a crispier, smokier skin. Both are delicious, so try the local version.
3. The Sansho Pepper
Don’t forget the green powder on the table. Sansho (Japanese pepper) is the standard condiment for unagi. Its citrusy, numbing spice cuts through the richness of the eel fat, making the meal refreshing in the heat.
4. Try Hitsumabushi
If you are visiting Nagoya, order Hitsumabushi. It is a set meal where chopped eel is eaten in three stages: first as is, then with condiments like wasabi and onions, and finally with broth poured over it like tea rice.
Sources & Further Reading
For those interested in the deep history of Japanese calendars and dietary customs, the following texts provide foundational context:
- The Manyoshu (Collection of Ten Thousand Leaves): Japan’s oldest poetry anthology (8th Century) contains poems by Otomo no Yakamochi recommending the eating of eel to combat summer weight loss, proving the health connection predates the Edo period marketing.
- Nihon Shoki (The Chronicles of Japan): While it does not mention the specific unagi custom, this 8th-century text details the adoption of the Chinese calendar system (Tenkan-Junishi) in Japan, which established the cycle of the “Day of the Ox.”