The Earth Cycle Days of the Ox

Today was an Earth Cycle Day of the Ox (土用の丑の日 doyo no ushi no hi). On this day Japanese people eat eels. And the full story is even better than this two-sentence summary.

The old Japanese calendar, drawing on the Chinese tradition, used the elements to distinguish between seasons. As everyone knows, there are five elements: earth, fire, water, gold, and wood. The latter four of these were assigned to the four seasons. The fifth became the Earth Cycle, which was assigned to the last 18 days of each season. Thus, all five elements got an equal share of the year.

So much for seasons. Months are irrelevant to this discussion, so I’ll pass over them. How about weeks? They revolved around the 12 animals of the Chinese zodiac: Rat, Ox, Tiger, Hare etc. There was also the rokuyo system but I won’t get into that either. Anyway, 12-day week, 18-day Earth Cycle, so most years there are two Days of the Ox in every Earth Cycle.

What does this have to do with eels? Well. The prevailing theory is that the Edo period teacher and inventor Hiraga Gennai was approached by some eel vendors having trouble selling their goods in the summer of 1822, even though eel is a traditional summer food. He drew up some slogan boards saying “Eat Eel on the Earth Cycle Days of the Ox”, apparently since ox (ushi) begins with the same syllable as eel (unagi). Why not just every day of the ox? Well, the summer Earth Cycle happens to dip into the hottest days of the year, so the sign would remind people that eel was a good food to eat in that weather.

The slogan boards were an instant hit, and the advertising spread throughout the country–in 1822. The calendar was reformed, the months were renamed, the complicated association with the elements was forgotten, the 12-day week was exchanged for a 7-day one–in the 1870s. Western buildings sprang up throughout Japan–in the 1880s. Baseball, curry, and steak became popular foods–in the 1890s. The empire conquered Korea and Taiwan, entangled itself in unwinnable wars, and lost everything. America took over for a few years and left. Cars were manufactured. Robots were invented. And in the 21st century still, every year the restaurants and grocery stores post up signs: “Eat Eel on the Earth Cycle Days of the Ox!”

Few people in Japan know what the terms Earth Cycle or Day of the Ox mean these days. Most likely nobody at all could tell you when an Earth Cycle is off the top of their head. (The Cycle has been neglected; lacking an official astrological recalculation, it is slowly drifting backwards into July and will reach early July by 2100.) But the saying remains.

The World’s Top 5 Most Obnoxiously Long-Lived Advertising Slogans

5. “A peach / Looks good / With lots of fuzz / But man’s no peach / And never wuz / Burma-Shave”, etc. (1927)

4. “All The News That’s Fit To Print” (1896)

3. “Ivory Soap: 99-44/100% Pure” (1891)

2. “They come as a boon and a blessing to men, The Pickwick, the Owl and the Waverley Pen” (1869)

1. “Eat Eel on the Earth Cycle Days of the Ox!” (1822)

Posted: July 21st, 2011 | Japan 2 Comments »

2 Comments on “The Earth Cycle Days of the Ox”

  1. 1 Avery Morrow's Internet Fancy said at 4:29 am on May 23rd, 2012:

    […] Earth Cycle […]

  2. 2 Avery Morrow's Internet Fancy » Japan’s year 2033 problem said at 3:57 am on December 10th, 2012:

    […] used for a number of things, like astrological calculations, old festivals, and determining the Earth Cycle Days of the Ox. Alas, all this will go awry in the year 2033, when the calendar will be unsure what year it is for […]