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April 01, 2020

Jomon Calendar and Wosite Documents

by Harriet H. Natsuyama

Japan-Insights Expert Harriet H. Natsuyama ,  visiting Scholar at the Kanayama Research Center shared her research on calendar systems - such as the one she presented in great detail at Japan-Insights.jp in her eassay Jomon Astronomy, the Solar Calendar of the Kanayama Megaliths .

Harriet H. Natsuyama

Mt. Kasagi, Mt. Ena, and Achi Shrine in the Nakatsugawa region, bordering the prefectures of Gifu and Nagano ©Google Maps


This article extends the recently reported findings of Kobayashi and Tokuda about the solar calendar of the megaliths in Hida Kanayama, Gifu prefture.

Viewed from Nakatsugawa, the 2,191m Mt. Ena straddles the border of Gifu and Nagano prefectures

Possible System of Megaliths: From Mount Kasagi in Gifu to Achi Shrine in Nagano

The thesis about the megalithic calendar system of the previous post may be supported by ancient Jomon documents. The three locations – Mt. Kasagi, Mt. Ena, and Achi Shrine – play an important role in the Jomon civilisation. They are centered around Nakatsugawa and cover an east-west spread of about 90 kilometers. The blue route has a driving distance of 58 kilometers.

Koyomi, meaning calendar, written in Wosite characters

Wosite Jomon Documents

In addition to my work with the Kanayama Megaliths, I have studied ancient documents written in the Wosite language of the Jomon period. These documents are not well known in Japan, even less in Western countries. The Wosite documents Hotuma Tutaye (also written Hotsuma Tsutae) and Hutomani (Futomani) are at least 2,000 years old. They represent a possible connection between the solar calendar of the megaliths and the ancient Jomon calendar. The Wosite word for calendar koyomi is still in use today.

Looking west to the winter solstice sunset from the Ena Jinja lower shrine

Omoikane Achihiko, Jomon Calendar Maker

The Wosite documents quote a prominent scholar of his day, Omoikane Achihiko. He was appointed as the first Hiyomi no Miya, whereby hiyomi refers to the solar calendar (koyomi), and miya indicates a high social position.
Omoikane took responsibility for the transformation of the lunar calendar into a solar calendar. He is remembered as a deity in shrines around the towering 2,191m Mt. Ena, which borders the prefectures of Gifu and Nagano.
The enshrined gods (kami) of Ena Jinja are Isanami and Isanagi, the parents of his wife Wakahime. The inner shrine, okumiya is located on the top of Mt. Ena and the more accessible lower shrine is on the western foothills of the mountain. The prayer hall of the latter faces a notch in the mountain ridge which indicates the direction of the winter solstice sunset.

Middle shrine of Togakushi Jinja

Omoikane no Kami

The great Togakushi Jinja in northern Nagano enshrines Omoikane, who is considered the god of wisdom, learning, and scholarship, and his two sons: the first, Tajikarao, in the Oku-sha and the second, Uwaharu, in the Hoko-sha of Togakushi.

Maemiya shrine of Achi Jinja, the memorial to Omoikane Achihiko. © Watari Kayo, November 2019

Achi Jinja

It is said that Omoikane Achihiko's found his final resting place in the Achi Jinja shrine in the town of Achi, southern Nagano, to the east of Mt. Ena. This shrine is considered to be the original one built before Togakushi Jinja.
The original location of Achi Jinja was the Motomiya, also called Okumiya, an ancient place of worship. There is an Iwakura stone to which the revered kami are said to descend. The stone is said to be aligned with the four cardinal directions and the winter solstice sunrise. The kami are Ame no Yakokoro Omoikane no Mikoto and his son Ame no Uwaharu no Mikoto.

Concluding Remarks

In modern Japanese, there are completely different variants for the writing of the names Omoikane, Ena, and Achi. These inconsistencies indicate that these names must be very old, originally written in Wosite characters. It must have been much later that different ways of writing them in kanji developed. Perhaps it was Omoikane Achihiko himself who established the Jomon megalithic solar calendar system. That is why we are enthusiastic about Kobayashi's and Tokuda's findings as reported in previous articles and the Japan-Insights topic on Jomon Astronomy. Carrying out fieldwork and analysis, running astronomical software, researching ancient documents, and learning about the history of shrines lead to revelations about the broad and deep extent of Jomon knowledge and achievements.

Additional information about Wosite and Omoikane can be found here:

© all photos Harriet Natsuyama (spring 2019) unless stated otherwise.

Learn more about the Kanayame Megaliths by reading Harriet Natsuyama's article Jomon Astronomy, the Solar Calendar of the Kanayama Megaliths. at Japan-Insights.jp!

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