Unveiling Doyo: Japan’s Season of Earth and Eel
If you find yourself wandering the humid streets of Tokyo or Kyoto in late July, you will undoubtedly notice a sudden, synchronized culinary shift. Convenience stores put up banners featuring grilled eel, luxury restaurants boast long queues, and the savory scent of soy-glazed kabayaki fills the air. You have entered the most famous period of Doyo (土用).
While often synonymous with eating eel to combat heat fatigue, Doyo is actually a profound concept rooted in ancient philosophy that dictates the rhythm of the Japanese calendar. For the cultural traveler, understanding this season unlocks a deeper appreciation of how Japan harmonizes with nature’s cycles.
Introduction to the Season of Earth
In the West, we typically view seasons as four distinct blocks of time. In traditional Japanese culture, however, the transition between these seasons is just as important. The term Doyo literally translates to “Earth use” or “Earth period.”
Technically, Doyo occurs four times a year—lasting 18 to 19 days before the beginning of Spring, Summer, Autumn, and Winter. However, in modern parlance, when Japanese people say “Doyo,” they almost exclusively refer to the Summer Doyo (late July to early August). This period is notorious for its oppressive humidity and heat, making it a time when health and stamina are prioritized above all else.
Origins: The Five Elements
The concept of Doyo is derived from Onmyodo (The Way of Yin and Yang) and the Chinese Five Elements theory (Wu Xing). According to this philosophy, the universe consists of Wood, Fire, Metal, Water, and Earth.
- Spring is associated with Wood.
- Summer is associated with Fire.
- Autumn is associated with Metal.
- Winter is associated with Water.
But where does Earth fit in? Ancient scholars assigned Earth to the transitional period between the seasons. Earth is seen as the element that facilitates change, allowing the old season to fade and the new one to bloom. Therefore, the 18 days of Doyo are considered a time of fluctuation and instability, ruled by the Earth element.
Legend: The Eel and the Inventor
The most pervasive custom of Doyo is Doyo no Ushi no Hi, or the “Day of the Ox during Doyo.” On this specific date, millions of Japanese people eat Unagi (freshwater eel). But why?
While eel is nutritious and rich in Vitamin B1 (helpful for fatigue), the tradition is largely attributed to the marketing genius of Hiraga Gennai, an Edo-period polymath, inventor, and writer.
The Story of Gennai
Legend holds that in the 1700s, an eel restaurant owner was struggling with business during the hot summer months. Eel was traditionally considered a winter food, as the high fat content was deemed too heavy for summer. Desperate, the owner asked Hiraga Gennai for advice.
Gennai drew on folklore stating that eating foods beginning with the sound “U” on the Day of the Ox (Ushi no Hi) brings good health and luck. He painted a sign for the shop that read: “Today is the Day of the Ox.”
The sign was a hit. People flocked to eat Unagi (which starts with “U”), hoping to ward off the heat. The custom spread like wildfire across Edo (Tokyo) and eventually the whole of Japan, turning a slow business season into the busiest time of year for eel merchants.
Modern Culture and Customs
Today, Doyo is less about agricultural superstition and more about seasonal wellness.
The Culinary Experience
Department stores and supermarkets set up massive displays of grilled eel. Prices for domestic unagi can skyrocket during this week. It is eaten specifically to gain stamina (seiryoku) to survive the remainder of the brutal Japanese summer.
Ushi-yu (Ox Bath)
Beyond food, there is the tradition of Ushi-yu, or bathing on the Day of the Ox. Historically, this meant bathing in water infused with peach leaves or medicinal herbs. In modern times, many Sentō (public bathhouses) offer special herbal baths during Doyo to help prevent heat rash and skin ailments.
Doyo-boshi
Because the Summer Doyo usually coincides with the end of the rainy season and the start of intense sunshine, it is traditional to perform Doyo-boshi (Doyo airing). This involves airing out books, kimonos, and clothes to prevent mold and insect damage. Temples will often air out their ancient scrolls during this dry, hot window.
Traveler’s Tips for Doyo
If you are visiting Japan between mid-July and early August, here is how to navigate the season:
- Book Early: If you want to eat at a renowned Unagi restaurant (like those in Narita or Nagoya), reserve weeks in advance. The lines on the Day of the Ox can last for hours.
- Try the Variations:
- Kanto Style (Tokyo): The eel is steamed before grilling, resulting in a fluffy, soft texture.
- Kansai Style (Osaka): The eel is grilled without steaming, offering a crispy skin and rich flavor.
- Hitsumabushi (Nagoya): Chopped eel on rice, eaten three ways (plain, with condiments, and with tea/broth).
- Other “U” Foods: If you don’t like eel or find it too expensive, you can still participate! Try Udon (noodles), Umeboshi (pickled plums), or Uri (gourds/melon).
- Heat Safety: The Summer Doyo is statistically the hottest time of the year. Carry a parasol, drink electrolytes (Pocari Sweat is a local favorite), and embrace the slower pace of the season.
Sources & Further Reading
For those interested in the historical and calendrical roots of Japanese seasonality, the following texts offer deep insights:
- Nihon Shoki (The Chronicles of Japan): While primarily a mythological history, it contextualizes the importation of the Chinese calendar system and the adoption of the Five Elements theory in the Yamato court.
- The Writings of Hiraga Gennai: Various Edo-period collections detail the life and satirical works of the man who popularized the Unagi custom.
- Engishiki: An ancient book of laws and regulations that details seasonal rites and Shinto rituals associated with agricultural transitions.
Embrace the heat, savor the rich flavors of Unagi, and respect the pause that the Earth season demands.