Is Japan located on another planet?

This is what a PhD in physics asked me.

“Why do you ask that?”

“Because in your books about Yamabuki, there are only 12 hours in a day.”

Japan during the Heian period—794–1185 C.E., when the Tales of Yamabuki as well as The Tale of Genji are set—had no mechanical clocks. Nevertheless, to run society, people needed to know the time of day, the season, the month, and the day.

Days consisted of 12 hours based on the 12 zodiac animals, each Heian hour being equal to about two modern hours. In a moment I will get to why I deliberately used the word “about.”

Days were divided into six “hours” of daylight and six “hours” of darkness. Instead of midnight, the day started at daybreak. Only in the Meiji times, in 1867, did the day change at midnight.

What is fascinating is that there were always six “hours” of daylight and six “hours” of night irrespective of the time of year. In modern times, with mechanical and even atomic clocks, we accept that more daylight falls in summer than in winter. We might turn back or move our clocks forward twice a year. In Japan it was done 24 times a year—approximately every 14 to 16 days—so that the first light would always come during the first “hour” of the day, which was known as the Hour of the Rabbit, sometimes called the Hour of the Hare. Dusk would come at the Hour of the Bird, sometimes called the Hour of the Rooster.

If we were to measure the actual length of winter days using a modern timepiece, the Hour of the Rabbit would be shorter than two hours because the relatively shorter total daylight in winter would still be distributed into six parts.

The six nighttime hours in winter would absorb the extra darkness and be proportionately longer than the nominal two hours of our 24-hour clock.

All this kept the astrologers and priests busy, because every 14 to 16 days, the clocks had to be adjusted. “More on that in a minute,” which by the way, is an idiom the Japanese of the era would not have used, because our modern concept of sixty minutes to an hour and sixty seconds to a minute is highly tied to mechanical clocks. The Japanese were no strangers to mathematics and dividing up circles, including the calculus which was independently discovered by the famous mathematician Seki Kōwa, 関 孝和, 1642-1708 C.E., and likely knew enough trig to divide circles into minutes, but they did not parse hours that way–not with the water clocks and hour glasses they used.

Japanese bell

The hours were announced by bells of Japanese design which were usually struck by swing a wooden beam again the side of the bell. Unlike Western bells with a clapper, the wooden beam produces a sharp reverb.

The Japanese did not number each hour, one thru 12. Rather, they rang the six daylight hours four thru nine, and the six nighttime hours, also four thru nine. We’ll get to the chart in a minute, but why start at four? Some say it was that one thru three bell-strikes were used for various calls to prayers. Others say the three bells informed people that they should get ready start counting—kind of like the “tune” Londoners hear just before the tolling of the hours when Big Ben is operating.

chinese zodiac hours
The modern hours ring the graphic, one thru twenty-four. Daybreak in Heian Japan is at six bells, Hour of the Rabbit, and dusk is also six bells, Hour of the Bird.

Interestingly, the Japanese “witching hour” is not at midnight, but at nominally 2 AM (1 AM–3 AM) and is known as the Hour of the Ox. Many Westerners will agree that this corresponds to the biorhythms of many non-Japanese.

To further embellish this, there were five vigils (watches) starting at the Hour of the Dog (five bells) and ending at the Hour of the Tiger (seven bells). The longest tolling of bells in the night was nine bells at the Hour of the Rat, sometimes called the Hour of the Mouse—maybe when “not a creature was stirring.”

That more or less takes care of the day, but the day has to fit into the calendar.

In the Heian period (and until 1867), each month began on the dark moon, also know as the new moon. The full moon would come on the 15th day and the month would end approximately on the 28th, sometimes the 29th, and even the 30th day of the month.

Japanese did not have the western concept of the seven-day week, though they certainly could count to seven. What they had instead was the concept of the solar stem, of which there were 24.

Telling time in Heian Japan Heian hours, Japan, Japanese calendar, lunisolar calendar, Ogane sound, Seki Kōwa, solar stems, time measurement, zodiac, 関 孝和
The graphic above gives the Chinese names for the solar stems. The Japanese did not know of corn in the Heian period. They are famous for rice.

In modern times we are used to a 360-degree circle, which seems quite “natural” to us. Each of the 24 stems would be 15-degrees.

Since the orbit of the Earth, as Kepler uncovered, is not a perfect circle but an ellipse, there are 24 periods when the Earth moves 15 degrees. In the modern calendar, there are 26 two-week periods. This means that a solar stem won’t be exactly 14 days but will be longer by a day or two to stay in sync with the sun. And it is at the beginning of each stem that the daylight and nighttime hours are changed in length to keep it at six daylight and six nighttime hours.

The first solar stem of the Japanese year starts on the first day of the year: Start of Spring, which, unlike the Western calendar, is not  in March. The Last Solar Stem (the 24th) ends on the last day of Major Cold. The beginning of the year in Japan, as measured by the Western calendar, would start somewhere between mid-January and mid-February, the variation resulting from aligning the solar stems with the lunar months.

Western Zodiac Signs
Above the graphic more or less uses the Japanese names for the stems in a circular representation instead of the more faithful elliptical one.

Thus, we know as Yamabuki and Tomoe ride up to the Shayō Tōge, the Sunset Pass, at Sunset on May 11, 1172, in the middle of a freak snowstorm, the author can say with some assurance that it happened at the Hour of the Bird on the 13th day of the 7th solar stem, two days past the full moon of the Flower Month.

If this post gets some interest, I will continue and explain how the author calculates that it is not only the Hour of the Bird, but is also the Day of the Earth Dragon, in the Month of the Fire Tiger, in the Year of the Water Dragon, all of which combine to let us know how well the day is aspected, as well as how it is that some years end up with a 13th month.



14 thoughts on “Telling time in Heian Japan”

  1. Brian from Chicago, just discovered this in the midst of my summer project reading The Tale of Genji. This is so clear and interesting and VERY useful to Murasaki readers.

  2. This IS very interesting. How great were outside (the country) influences in Yamabuki’s time. More!

    1. Hello Donna!

      As we already suspect, Yamabuki is as sharp in calligraphy as in swordsmanship and Lord Nakagawa is teaching her to not only write Chinese–aka The Land of the Yellow River Delta where the Sóng Dynasty rules (part) of the land–but also to speak the language. It will be revealed later how it is that Lord Nalkagawa can speak the Common Language (aka Chinese) even though he is not Chinese. In Cold Rain, Chapter Two, we hear Yamabuki announce that she intends to go to China and to Kara (Korea) to see the places for herself.

      We also see she has a writing box that appears in all three of the first books and will continue to play a role in the stories. She carries a book (more like a booklet) of Chinese poems she translates for fun, changing them around to make them Japanese (in cursive, the “women’s writing” like Murasaki’s Genji) and to fit her mood. We see that right off in Cold Blood.

      We also see the Taka remember when the Emperor lived on the Isle of Unknown Fires (modern Kyushu) and there was a lot of trading going on out of the Emperor’s capital on the south isle at the city of Dazifu. Three Japanese Emperors ruled from there until they decided to head back to Honshu. Chinese merchants still show up in Yamabuki’s time and the Taka are keen on getting Chinese technology in exchange for the most beautifully dyed color fabrics anywhere which the Chinese prize. And where do the Taka get horses, like Mochizuki, that are all-but Arabians? Doesn’t take much guessing.

      The ties outside Japan will increasingly draw Yamabuki and it is her intent to travel not only throughout Akitsushima (The Autumn Creek Land, also The Land of the Reed Plains, the ancient names the Chinese gave to Japan) but across the Leeward Sea (aka The Sea of Japan).

      Thank you for your support.

  3. Thank you for the very interesting blog. It seems very complex when compared to our linear prescriptive measurement of time.However it is natural and changes to match nature and the seasons rather than a clockwork machine.

    1. Living in the city where the nation’s atomic clock sits, it is sometime hard to remember how primitive cultures measured time. In my anthropology courses at the University, we read about cultures what did not need to know time any more precisely than (maybe) the day of the week.

      A professor of ethnomusicology spoke to us about his village in Africa where in the 20th century people agreeing to meet based on approximately how high the sun would be–and then they we meet at the appointed place.

      In the book Mirror On Man, reminds us of Western society where we go around with time-pieces literally strapped to our bodies.

    1. I asked Laura Scott, the series editor, if it might make sense to add this blog to the books series or maybe delay it until we issue the book, Yamabuki’s World, a companion to the text which describes the world she live in.

  4. That would be Great! I love books which explain the culture and history of a series I am reading. If you are going into the detail like you did in the blog, you should probably wait till the companion.

    1. It is a delicate balance. To the people living in this world, reckoning the time by the Hour of the Dragon is second nature and so in the flow of the world it just is. The writer might call attention that the sun was barely breaking the tops of the trees when the bells for the Hour of the Dragon tolled.Though there are some readers who love all the details of the Heian civilization, there are others who might find an explanation of what hour it is to be distracting.

      Some authors simply take the plunge and use hours and minutes, feet and miles, pounds and tons which for me breaks the fourth wall. Even the language–though I write in modern English and not Beowulf English which was spoken in England at the time of Yamabuki, I try to stay with modern words with old root. With the rarest or rare exception (I used the word travois in a yet to be published story) root-words spoken by farmers are Saxon while the samurai and kuge use some French roots and Latin root words. Other than travois, no word originates after 1800 and most all roots are earlier that 1700.

      When Yamabuki launches an arrow she can “shoot” it for this word does actually go back to Beowulf English, but to “fire” suggests gunpowder. Gunpowder was known to Yamabuki–the Taka got it from China (Qin, or Land of the Yellow River Delta) which the Chinese called Fire Drug, but which was not used for firearms as the latter were unknown in Japan in that era–it would be the Portuguese who would bring the gun to Japan. Earlier I had used “carriage” and now use the more accurate “cart” and have been correct in future printings. My hope is that the word choices and root words give the Autumn Creek Land stories an authenticity.

      1. Yes, I see what you mean. I’ve noticed in other books I have read, sometimes a word doesn’t seem quite right. Not wrong, but not quite right. On the other hand is the vehicle being used as a “carriage,” or a “cart”? Or both?

  5. Jishi Jeff Bickner

    AS a Zen Buddhist priest I was studying Dogen Zenji’s fascicled Uji from the Shogogenzo (circa 1200) . Uji is Being Time or Time Being and I began to wonder how the Japanese told time in the early 13th century. Your blog has been very informative. Thank you!

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