Trivia quiz for the Day of the Ox in midsummer: little-known facts about customs

It commemorates the day when people started eating beef.

The Day of the Ox has nothing to do with the custom of eating beef. Just as we still count years by the zodiac signs, days used to be counted by the same system as well, and one of those days was the Day of the Ox. Because it follows the twelve zodiac signs, the Day of the Ox comes around in a 12-day cycle. Additionally, the 'Doyo no Ushi no Hi' refers to the Day of the Ox that falls within the roughly 18-day doyo period, so in some years there can be two such days.

Changing of the seasons

“Doyō” refers to the roughly 18-day period preceding the first day of spring, summer, autumn, and winter. Therefore, it occurs four times a year. Among these, when people mention “the Day of the Ox during Doyō” on which eel is eaten, they are generally referring to the summer Doyō.

Kyoto Prefecture

According to the 2022 Family Income and Expenditure Survey by Japan’s Ministry of Internal Affairs and Communications, Kyoto Prefecture spent the most on grilled eel (kabayaki). While Shizuoka and Aichi are also famous for eel, it’s surprising that Kyoto ranks first. However, this survey does not include spending on eating out, so the ranking only reflects expenditures for consumption at home. If dining out were included, the results might be different.

blood

Eel blood contains a toxin called ichthyotoxin, which can cause symptoms such as diarrhea and vomiting if ingested. It may also cause inflammation from bare-skin contact, so it must be handled with care. Thorough heating renders it harmless, so properly prepared dishes like kabayaki are safe to eat.

October to December

Eel is often associated with summer, but its true season is from October to December, just before winter. That’s when eels are at their most delicious because they’ve stored up fat to get through the cold. In other words, the eel eaten in summer for the so-called Day of the Ox (Doyo no Ushi no Hi) is actually out of season. To help eel shops sell eel in summer, the custom was proposed of eating eel on the Day of the Ox.

In Kanto they split the fish from the back; in Kansai they split it from the belly.

For grilled eel (kabayaki), it’s traditional to split from the back in the Kanto region and from the belly in the Kansai region. One explanation is that Kanto was a town of samurai, so they avoided associations with seppuku and opened the eel from the back, while Kansai was a town of merchants, so the custom of “speaking openly” (literally, splitting the belly) led to opening it from the belly. It shows how local cultures and customs even influence cooking methods.

Soak in a hot spring

On the Day of the Ox during Doyo, there is a custom called ushi-yu: taking one’s time soaking in a hot spring or bath to care for a body tired from the summer heat. This practice is rooted across Japan, and Aomori Prefecture’s Ushi-yu Festival is especially well-known.