Category Archives: Seasonal observations

February 27/28 Leap-Year Observation of 2019


There is a leap-year spotlight observation that takes place on February 27/28 each year. The spotlight was observed in 2018 on those days. This is the return of the sunbeam of light to the tip of Stone b, which the sunbeam last visited the previous October 14. The return of the light is a similar phenomenon to that of the sunbeam on the Sekimen-ishi reported on here and here for 2019.

However, this year it rained and no spotlight could be seen.

We are looking forward to the October 14/15 spotlight on Stone b, which will indicate that the following year (2020) will be a leap year.





Return of the Light to Iwaya, 2019 February 16 and 17




2019.02.16 at 13:04 (L) and 13:22 (R)

In our previous post, we showed the photos taken by Chika-san on 02.21. We have now received photos from Sugisaka-san taken earlier, on 02.16 and 02.17. By comparing them, we can see how the spotlight on Sekimen-ishi changes from day to day. The pair of photos above were taken on February 16th.




2019.02.17 at 13:04 (L) and 13:22 (R)

The photos just above were taken the very next day at the same times. The first pair of photos is closer to the back wall, since the sun’s path on the 16th is lower in the sky than it is on the 17th. When compared with Chika-san’s photo of the 21st, the later day shows a narrow spotlight on Sekimen-ishi. Perhaps on the 22nd or 23rd the spotlight did not reach Sekimen-ishi at all.

The spotlight previously appeared on October 23, 2018. The report is given here. The observation then marked sixty days before the winter solstice.  You can refresh your memory of the Kanayama Megaliths solar calendar here.

We are grateful to Chika-san and Sugisaka-san for sharing their photos with us.





Return of the Light to Iwaya, 2019 February



12:42     12:52



13:02     13:25



13:37     13:42

Sixty days after the winter solstice, the spotlight returns to Iwaya-Iwakage. This is the spotlight that appeared in October of the previous year, sixty days before the winter solstice. See the report for October 2017.

These photos were taken by Chika-san on February 21, 2019. 

The first two photos show the triangular spotlight on the floor of the Iwaya approaching the Sekimen-ishi, which had been hewn out of the megalith thousands of years ago. 

The next two photos show the spotlight changing its shape as it illuminates the Sekimen-ishi.

Finally, the last two photos show the spotlight sinking and disappearing completely.

This beautiful light show takes place for about five days every February. It marks the return of the sun to the north after its sojourn southward to the winter solstice. It heralds that the spring equinox will take place in about thirty days. Such is the Kanayama solar calendar.

Thank you, Chika-san, for sharing your photos!



Miyajidake Hikari no Michi 2019 February

IMGP2630 chart
Directions of sunset as seen from Miyajidake Jinjya

In 2017, Chika-san reported on her visit to Miyajidake Jinjya to see the sunset of the Hikarinomichi. This year, she went there on Feburary 20. The day was cloudy, so she walked down to the beach.

IMGP2630 chart copy
Closeup of chart

She found there the chart shown at the top of this page. The location is 33deg 46min 36.5sec, 130deg 28 min 13.6sec. The center straight line is the line of sight from the shrine at about 12 degrees south of west. The line to the west is marked at zero degrees. The loop is that of the analemma which tells how fast/slow the actual sun is compared with the mean sun, on the days of the year. Times of sunset are given. The places where the sun sinks into the sea or an island are indicated at different days of the year. Extreme far left is the day of winter solstice at 28deg south of west. Ainoshima is the island where the sun sets on or about February 20; it is straight ahead of the shrine.

The following photos were taken 20 min before and just after sunset.


Guide Booklet for Kanayama Megaliths

KY-JIN cover



Kanayama Megaliths Guide Booklet

An English-language guide to the Kanayama Megaliths has been published by the Japan-Insights program of Toshiba International Foundation. The PDF can be downloaded from this URL. There are 28 pages. We hope you will find it an excellent and concise reference book to the viewing spots and solar observations at various times of the year.

Book on Kanayama Megaliths and the Solar Calendar

A book on the Kanayama Megaliths and their solar calendar is in preparation. Written in English and Japanese by the original researchers, the book will be the first thorough description of the megaliths and all their functions, and all the observations possible at the triple site.







Winter and Summer Solar Observations at Shrines and Kanayama


Winter at Ise Jingu. Photo by K. Sugisaka taken on 2019.01.27.


As you know from the previous post about welcoming the new year at Asadori Myoujin shrine, the winter solstice ceremony marks the beginning of a new year.

Ise Jingu in Mie Prefecture is an ancient Shinto shrine. Throngs of people visit Ise Jingu, especially in January. To view the sunrise over the Ise Jingu torii in winter is a popular and sacred event from ancient times until even now. 

When we received this photo from Sugisaka-san, although it was taken in the afternoon more than a month after the winter solstice, it reminded us of similar solar observations that take place at the Kanayama Megaliths. On the pages of Iwakage, Okunomichi, and WoshiteWorld, we have described other ways in which ancient people have watched the sun. 


Summer Observations at Kanayama Megaliths

For the readers of Iwakage’s blog, we remind you that the Kanayama Megaliths have solar observations before and after the summer solstice, at Senkoku-ishi.

3/21 – 9/23, 90 days before and after summer solstice, the sun rises over Stone C at Senkoku-ishi.


Sunrise over Stone C, summer.

4/22 – 8/20, 60 days before and after summer solstice, an arrow-shaped spot of light appears in the chamber of Senkoku-ishi, reaching the left end of a stone board on summer solstice day.


Arrowhead of light inside Senkoku Ishi, summer.

5/21 – 7/22, 30 days before and after summer solstice, a dashed line appears in Senkoku-ishi. A striking dashed spotlight appears which is enjoyed by many, year after year.


Dashed spotlight in Senkoku Ishi, summer 30 days before and after

Winter Observations at Kanayama Megaliths

10/23 – 2/20, 60 days before and after the winter solstice, at Higashinoyama, the sunrise is viewed between Stones R and S.


Winter sunrise at Higashinoyama, Stones R and S.

The above four images are from the Guidebook of Kanayama Megaliths.


Twenty-five days before and after the summer solstice in Honolulu, the sun will pass directly overhead at local noon. This, too, can be an indicator of summer solstice day exactly midway between the zenith dates. This event is popularly called Lahaina Noon.


Winter Solstice Sunrise Observation at Ise Jingu

Sugisaka-san has provided the following information about the sunrise event. On winter solstice morning, the sun rises over the center of the eastern torii at Uji bridge. One month prior to, and one month after, winter solstice day, the sun rises from the trees on the left of the torii. This page on the Ise Jingu website shows the winter sunrise event,  



Winter solstice sunrise at Ise Jingu, postcard by Kankan.






Winter Solstice 2018

IMGP2424 0904am

Higashinoyama winter solstice sunrise, 9:04 am December 24, 2018.


We reported on winter solstice 2017 at the Kanayama Megaliths. Winter solstice took place on Saturday, December 22, 2018 at 7:22 am in Japan. It was cloudy on the 22nd and the 23rd. On the 24th, a group hiked up Higashinoyama for a successful observation. Above is Chika’s photo of the rising sun as seen from the observing megalith, on December 24, 2018 at 9:04 am. Although the time of sunrise was 6:58 am, it took two hours for the sun to be seen at the megalith, even though it is on top of a mountain, due to the terrain and the trees.


The group returned to Senkoku-Ishi and waited for the sunset. Official time of sunset was 4:45 pm, but the sun sinks out of sight earlier. The view from between Stones B and B’ at 4:03 pm is magnificent, as seen in Chika’s photo below.

IMGP2442 B-B'



The Simulator near Senkoku-ishi models the observation of sun beams at five different times of the year. In the early afternoon of winter solstice day, December 22, 2018, at 13:29:00, the following photo was taken by K.S.