Seasonal Calendar of October

In this 'Seasonal Calendar', I would like to introduce traditional Japanese seasonal events, which come down to Japanese's modern life for the time being.

This Season's Traditional Events

This month I'd like to pick up Juugoya in this 'Seasonal Calendar'.

Jugoya also known under the name of (O)tsukimi ( literally, viewing the moon ) or Chuushuu no Meigetsu ( literally, the most beautiful moon on August 15th of the lunisolar calendar ) in Japan, is a custom to admire the beauty of the moon on the 15th day of the 8th month, based on the lunisolar calendar.

But why does it have to be August 15th? Besides, it's already October. What's the event of August 15th got to do with October? Well, there are good reasons.

First of all, the date of this event August 15th is the date based on the lunisolar calendar, which had been put to use in Japan until 1873. The lunisolar calendar generally known in Japan as Kyuureki or Inreki, must have been imported to Japan from China in the eraly days of Japanese history. But they were abolished by the end of 1873, and the new Gregorian Calendar was adopted from the beginning of the following year, 1874.

Some of the traditional Japanese events are still held based on the date of this lunisolar calendar, in consequence the date of these events tend to differ in our present Gregorian Calendar. This is why Juugoya is held during this season. It is usually celeberated between around mid-September to around the beginning of October of the Gregorian Calendar. And this year, Juugoya is on October 6th, Friday.

Why August 15th?

Now, you might have understood why an August event is talked about in October. But are there any particular reasons to hold this event of viewing the moon, on this particular day?

As you can guess from its name, the lunisolar calendar usually corresponds to the age of the moon, meaning that the middle day of each month which is the 15th, falls on a full moon. So the event of Juugoya was to be held on the night of a full moon. After all, it's something like a moon viewing party. The moon itself was the life of the party, and it couldn't be left out. Incidentally, this year the full moon would appear on the night of October 7th, Saturday.

But if the lunisolar calendar corresponds to the moon age, then there must be a full moon every month. Why did it have to be August, and not any other month? Besides, why is the Juugoya event of this year, held a day earlier then the date of a full moon? Isn't it supposed to be an event to admire a full moon?

Seasonal Restrictions

As you might already know, Japan is a country with moderately warm and moist climate. Especially during spring to summer when the temperature rises, we also experience a high rise in humidity, which makes the spring and summer season in this country, inappropriate for viewing the moon since they look blurred because of the moisture in the air.

On the other hand, winter would be a suitable season for observing stars or the moon, since the air is dry compared to the spring or summer season, but it's a bit too cold to view the moon and party outside.

That leaves us only autumn for a suitable season to admire and enjoy the beauty of the moon. The air becomes dry as the temperature slides down gradually, and it won't be either too hot nor too cold to gaze at the moon outside, even if you stayed outside for hours. The autumn season corresponds to July, August and September in the lunisolar calendar, so this seasonal restriction could be one of the reasons.

Food Cultural Reason

Another reason and probably the most convincing, can be thought that it was because of the harvest season of taros, which fell on the 8th lunar month. Although this event of Juugoya had been under much influence of the Mid-Autumn Festival imported from China, the background of this event in Japan, traces back to as far as 25 thousand years ago.

About that time, part of the Japanese ancestors are said to have come to Japan from the southern islands, where there were certain food culture to eat yams and taros. However, the circumstances were different in Japan, from the tropical climate of the southern islands where a knot of our ancestors came from, and many of the yams and taros which they had brought along with them became extinct, not being able to fit into its new surroundings.

Though there were some that barely survived through this change of environment, Satoimo ( literally, village potatoes, taro corms or aroids that were cultivated around human settlements in Japan ) wich is the survivor of the taro family, and Yamaimo ( literally, mountain potatoes, glutinous yam that grew wild in the mountains ) from the yam family. These two come down to today, appearing on tables of Japanese homes mainly as side dishes.


Satoimo are often used as offerings in the Juugoya event, I guess because many of them come in round circular forms, compared to Yamaimo which have long sword-like appearance. Originating from this offerings, the event also bears the name of Imo-Meigetsu ( literally, aroids and the moon on a clear night ). This fact also seem to give credence to the theory, that Juugoya event has been held according to the harvest season of Satoimo.

Date Gap Between Full Moon and Juugoya

As for the gap between the date of the full moon and the date of Juugoya in our present calendar, the main reason is thought to be the orbit of the moon. It is said that the moon's orbit is not a complete circle, and this allows the number of days needed for a new moon to grow into a full moon, change within 13.8 to 15.8. The average number of days needed for a crescent to grow into a full moon, is 14.76 days according to the Gregorian Calendar, while the average in the lunisolar calendar is 14. This creates a time lag of 0.76 day.

full moon

Consequently, the date of the full moon tend to come 0.76 day later, than the date of August 15th of the lunisolar calendar. This may explain why the date of the full moon this year which is October 7th, comes after the festive day of Juugoya on October 6th. This year, many of you might have been able to enjoy a beautiful full moon since we had clear sky, but usually there seems to be less chances to see a full moon on Juugoya, for Japan annually experiences much rain during this typhoon season.

No Moon on Juugoya

It is said that old books written during Edo era (1603-1868), even has it that the full moon on this festive day 'cannot be seen in nine years out of ten', due to continual rain or typhoons during this season. And because the Japanese ancestors had great passion for the moon, they created unique words longing for a chance to see it even after the event.

When people couldn't see the moon on Juugoya which literally means 'the 15th night', they awaited for the moon to rise calling the 16th night as Iza-yoi ( come on, there now it's evening ), 17th night as Tachi-machi-duki ( a moon seen after one stood waiting ), 18th night as I-machi-duki ( a moon seen after one sat waiting ), 19th night as Ne-machi-duki ( a moon seen after one lay waiting ), 20th night as Fuke-machi-duki ( a moon seen waiting even longer ), going so on until the 30th night as Tsu-gomori ( a night without moon ), awaiting for the moon altering day by day in appearance.

Japanese Passion for the Moon

These particular Japanese expressions, seem to tell that Japanese had a great passion since the ancient days, especially for a full moon which is known under the name of Mochi-duki ( literally, desired moon ).

In the days way back before even the lunisolar calendar was put to use, darkness was a world of horrid beasts, monsters and creatures, to the people in those days. Therefore, a night of complete darkness without moonlight, certainly must have been one of their most frightening experiences. How grateful and relieved those people might have felt all the more, when a full moon rose shining down its soft light upon the earth and the world. Regarding such things, it is not hard to imagine how important a full moon was, to the people in those days.

The importance of a full moon might also agree with the fact, that these people who held the plow, relied on the phases of the moon to know the right time for planting and harvest, until a practical calendar was put to use. And as they also accepted the constant movement of the regular phasing of the moon as death and rebirth, the moon itself became worshipped among ancient people. Since the moon was then believed to be at the peak of its lively energies on the night of a full moon, celebrations are thought to have been held on such nights, which later is thought to have changed into the custom of Tsukimi ( literally, moon viewing ), under influence of Chinese culture of the Mid-Autumn Festival.

Offerings for Juugoya

In the sense that farm work in ancient Japan relied on the phases of the moon, and this Juugoya or (O)tsukimi event had a character to celeberate harvest, decorations for Juugoya are said to originate mostly from the harvest of this season. Susuki ( Japanese silver grass or Eulalia ) and (O)dango ( round rice dumplings ) are the two most common decorating items seen throughout Japan, while Aki-no-Nanakusa ( seven autumnal flowers ) or other seasonal fruits and vegetables are additionally presented as offerings according to each region.

silver grass

Susuki ( Japanese silver grass or Eulalia ) is said to have come frome the first crop of rice of that year, which the Japanese ancestors prepared as offerings to thank for harvest. The golden eared first crop of rice offered to the full moon on Juugoya, originally was a symbol of thankfulness for the harvest, but it was later replaced by Susuki which also come into ears by this season, when the Japanese lifestyle has changed and not every homes lived on farming.

(O)dango is a dumpling made of rice powder, usually eaten sweetened with Anko ( sweet bean paste ), sweetened Kinako ( soy bean powder sweetened with sugar ), or with Shou-yu ( soy sauce ) based salty-sweet sauce. It is said that (O)dango has its roots in cooked Kinu-katsugi ( literally, wrapped in clothes, young and small taro corms or aroids in their skins ), which were also presented as offerings to thank for harvest in the early days of Japanese history.

It is said that since Emperor Uda had prepared (O)dango for the moon viewing event at court in 897, Kinu-katsugi were replaced by (O)dango which come down to today. Now there are still customs left throughout the country, to set 15 (O)dango on trays or plates for Juugoya ( literally, 15th night ) in connection with the event's name. Incidentally, it is told that in the eastern areas, the (O)dango are shaped round resembling the shape of a full moon, while in the western areas they are shaped oval, resembling the shape of Kinu-katsugi.

Related to the Juugoya event, there is also a similar event called Juusanya ( literally, the 13th night ), to view and admire the beauty of the moon approximately one month after the Juugoya, on the night of September 13th of lunisolar calendar. This year it's November 3rd Friday. In Japan, Juugoya and Juusanya are often talked about in a set, and it is thought to bring bad luck to celebrate only Juugoya.

This event also known as Nagori-duki ( literally, moon left in the sky ) or Nochino-tuski ( literally, the later moon ), is said to have originated with Japan without being influenced by neighboring countries, such as China or Korea. Well, regarding the fact that Kuri ( sweet chestnut ) which are often presented for Juusanya offerings, are said to be eaten in Japan since Joumon era ( around B.C.7000-around B.C.250 ), the theory that has Juusanya as a Japan originated event, I think, can be thought reliable.

As the time of Juusanya corresponds to the harvest season of Edamame ( green soybean ) and Kuri ( sweet chestnut ), both of them are offered to celebrate this event, probably as to express thankfulness of the harvest just like the Susuki or (O)dango. Soybeans and chestnuts were originally the offerings for Juusanya, though there seems to be cases to present them as offerings for Juugoya too. Still this event of Juusanya also bears the name of Mame-meigetsu ( literally, soybean and the moon on a clear night ), or Kuri-meigetsu ( literally, sweet chestnut and the moon on a clear night ) after these offerings.

There seems to be other additional offerings, such as Sake ( rice wine ) brewed with the year's first crop of rice or Akino-nanakusa ( seven autumnal flowers ), but this Juugoya story is getting too long, so I'll guess I'll explain about them some athoer time.

Juugoya Related Stories

Actually, there are a couple of Juugoya related legends and I'd love to tell them all, but as I've said before this whole story is getting too long, I'll just pick up two of them here.

Tsukuyomi and Ukemochi
Tsukuyomi-no-mikoto, one of the deities that appear in the ancient Japanese myths of Kojiki ( A Record of Ancient Matters ) or Nihon-shoki ( Chronicles of Japan ), was a deity that ruled the night world and the sea. She took control over the phases of the moon, and the rhythm of the tides as well.

One day when Tsukuyomi visited another deity called Ukemochi ( literally, food saver ), she caught Ukemochi trying to entertain her by bringing out cereal grain or animals from his mouth. Tsukuyomi was so disgusted at what she saw, that she killed Ukemochi from anger. But from the dead body of Ukemochi, there came out a variety of grain , rice, barnyardgrass, millet, soybean, adzuki bean, together with cows, horses and silkworms.

Amaterasu-ohmikami, a deity ruling the heaven and the sun who was also a sister of Tsukuyomi, was infuriated at what her sister had done to Ukemochi. She called her 'a bad deity' and told her that she didn't want to see her ever again. And so it became for the moon to be able to shine only during the night time, while the sun was not in the sky, and the two of them the sun and the moon, came to shine seperately in the sky.

About the Rabbit on the Moon
Many Japanese think of rabbits when talking about moon. This is because Japanese tend to see the pattern on the moon, as a rabbit pounding Mochi ( rice cake ) instead of a walking man. But in China, the pattern seems to be recognized as a rabbit pounding medicinal herb instead of rice cake, and the moon seems to be accepted as an immortal place. This may be what you call 'different countries have different foods'.

However, you can see certain similarity with this Chinese recognition in Taketori-monogatari ( The Tale of the Bamboo-Cutter ), one of the most well-known old stories in Japan. In this story, there are supposed to be a herb called Fushino-kusuri ( literally, immortal medicine ) on the moon, and Kaguya-hime ( the moon princess ) leaves some of that herb for the old man who had been nice to her during her stay on earth. The old man brings the herb to the emperor as a gift, but the emperor said it wasn't necessary and burnt them all at the mountain of Fushi ( literally, immortal ), which later is told to have become Mt. Fuji.

Last Modified Oct.28th, 2006

Site of Reference

Mid-Autumn Festival - Wikipedia ( English )


Japanese Mythology - Wikipedia ( English )


Nenjuugyouji-Sekku ( Japanese )


Koyomino-page ( Japanese )


Nihonno Shinwa to Kodaishi to Bunka ( Japanese )


Uzukitakare-mini ( Japanese )