Endangered Butterfly: Gifu Cho


Endangered Butterfly:  Gifu Cho

Photo by Kazuo Sugisaka, 2014.04.12

The Japanese luehdorfia (Luehdorfia japonica) is endemic to Japan, as it is found only on the main island of Honshu. This species was discovered in Gifu prefecture in 1883. The Gifu Cho, as it is called by the locals, is strikingly beautiful with its bold black stripes.

The adult Gifu Cho lives only a week in the foothills of central Japan after it emerges in late March – early April spring season. Adults mate and eggs are laid. Eggs hatch in April, and the caterpillars feed on wild ginger leaves. After a month, they pupate and then hibernate for ten months. The new butterflies emerge the following spring, to continue their life cycle.

On April 7, 2019, ten members of the Association of Luehdorfia gathered near Kanayama Megaliths to look for the butterfly.  The actual observation site is Ikenoshimakouen, an island park. It is some 5km south of the megaliths and 600m south of the Soshino Hachimangu Shrine. In the middle of the Maze River is a small island called Ikenoshima. The local people have been safeguarding the site for the Gifu Cho.

It was disappointing that none were observed this year. It is worrisome, and some fear that the Gifu Cho is becoming endangered as their habit is being destroyed by agriculture and urbanization.






Starry Night Over Iwaya-Iwakage

Stars over Iwaya

Night sky over Iwaya-Iwakage

Photo by K. Sugisaka


Although it rained on February 27, 2019 and the leap-year spotlight could not be seen, it was clear at night. The above 498-second photo was taken by Sugisaka-san at 20:32. If you look carefully, you can see the star streaks as the circumpolar stars circle the north polar axis. On the lower left is the dim image of the megaliths of Iwaya-Iwakage.




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.