Unagi (鰻) on Doyo no Ushi no Hi (土用の丑の日)

Unadon at Sukiya

Today is "Doyo no Ushi no Hi (土用の丑の日)," a day in Japan traditionally associated with eating unagi (鰻) or Japanese eel.  Many restaurants that do not normally offer unagi will feature it on their menu during this time of year.

So, what exactly is Doyo no Ushi no Hi?  "Doyo (土用)" refers to an 18-day period before the start of each season according to the traditional Japanese calendar.  "Ushi no Hi" literally translates to "Ox Day (丑の日)," one of the 12 animals in the Chinese zodiac.  While the zodiac is commonly used for marking years, it was also used to mark days.  Therefore, Doyo no Ushi no Hi is simply Ox Day during the Doyo period.  Although there are four Doyo periods each year, "Doyo" generally refers to the one just before autumn, which falls in late July to early August.

Unagi is actually in season around October to December.  Then why is this day associated with eating unagi?  The tradition of eating foods that start with the sound "u" in Japanese, such as umeboshi (pickled plums), udon (noodles), or uri (melon), on Ushi no Hi was believed to bring good luck.  The association of unagi with this day is thought to stem from a catchphrase created by Hiraga Gennai (1729-1780), an Edo-period scholar, who coined the phrase "Unagi on Doyo Ushi no Hi" to help a struggling unagi restaurant owner increase sales during this period.