Megalithic Calendar System in Gifu Prefecture – 2. System of Solar Megalithic Sites

Fig. 16. The megaliths of Nakatsugawa city and relation to the solar path, plus Jomon sites indicated. 

Investigation of Megaliths in the Area

This post follows Part 1. Kobayashi and Tokuda noticed that the megaliths of Maruyama Jinja in Nakatsugawa City were oriented toward the equinoctial sunrise and sunset. For the east and west cardinal directions to be accurately known, directions to sunrises and sunsets at times of summer and winter solstices are essential (because the east-west line bisects the angle between the solstice directions). They asked, what other megaliths were a part of the Jomon solar calendar system?

Layout of Solar Megalithic Sites and Jomon Settlements

In March and April, 2019, they started to investigate the megaliths in the environs of Maruyama Jinja. They produced the map called Fig. 16. On this map refer to Maruyama Jinja labeled in black, somewhat to the right of center. The range of sunrise directions from solstice to solstice is shown in pink. Not far, and to the north-east of Maruyama Jinja lies Sengeyama, with a blue arrow pointing to it from the summer solstice sunrise direction. At the center top is the site of the Iwayama megaliths with equinox sunrise direction indicated (blue arrow). Blue arrows point at Kasagiyama from equinox sunrise and winter solstice sunrise directions. Kasagiyama is 12km to the west of Maruyama Jinja. Finally, note the many Jomon archaeological sites indicated by the red dots. 

Photos of Solar Megalithic Sites by S. Tokuda

The megaliths of Sengeyama (Fig. 17) observe the rising sun on summer solstice; the megaliths of Iwayama (Fig. 18) look to the rising sun on the equinoxes; and Kasagiyama megaliths (Fig. 19) to the winter solstice rising sun. It is noted that Kasagiyama and Sengeyama megaliths are flat on top.

Fig. 17.  The megaliths of Sengeyama are oriented toward summer solstice sunrise.

Fig. 18.  The megaliths of Iwayama are oriented toward the equinoxes.
Fig. 19.  The megaliths of Kasagiyama are oriented toward winter solstice sunrise (lower red arrow, left orange arrow). There are spaces for equinox rising sun to penetrate (upper red arrow, lower right orange arrow).


Therefore, it can be concluded that there may have been a system of cooperating megalithic sites for the determination of an accurate solar calendar in Jomon times. This system may have been designed and constructed by the Jomon people who lived in the area.

Jomon Calendar

The editor of this blogsite adds a final comment on the findings of Kobayashi and Tokuda. We believe that their discoveries are supported by an ancient historical record written in the Wosite language. The WoshiteWorld blogsite has posted that: In chapter 23 of the Hotuma Tutaye document, it is written that Achihiko Omoikane made the lunar calendar into a solar calendar by introducing a leap-month. He was given the title of Hiyomi-no-miya, the one who knows the solar calendar. He lived in that part of Gifu prefecture and is said to be buried at the Achi Jinja in Nagano prefecture, almost due east of this part of Gifu.

Data from:  “The Kanayama Megaliths and Funa Iwa Solar Observation System of Gifu Prefecture,” Y. Kobayashi and S. Tokuda, J. Astro. Archaeol. Soc. Japan, Vol. 1, No. 1, 1-9, 2019. All figures and an advance copy of the paper were provided by S. Tokuda, for which we are very grateful.


2 thoughts on “Megalithic Calendar System in Gifu Prefecture – 2. System of Solar Megalithic Sites

  1. Pingback: Megalithic Calendar System | WoshiteWorld

  2. Pingback: Megalithic Calendar System in Gifu Prefecture – 2. System of Solar Megalithic Sites — Iwaya-Iwakage of Kanayama Megaliths | Die Goldene Landschaft

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