The Changing Length of Earth’s Day


Have you ever wondered how long is an Earth day, and is it changing? Well, although the day length is nominally 24 hours, it is not exactly so. It can vary from day to day, as well as from year to year. The amount of change may seem miniscule, and yet it will affect us as early as New Year’s eve, 2016.

A Leap-second will be added on December 31, 2016


“The U.S. Naval Observatory announced on July 6, 2016 that a leap second will be added to official timekeeping on December 31, 2016. That means your day and year – and everyone’s day and year – will officially be one second longer.”

Earth’s day-length is variable

The U.S. Naval Observatory chart above and article describe the variable length of day, http://tycho.usno.navy.mil/leapsec.html:

“The length of the mean solar day has increased by roughly 2 milliseconds since it was exactly 86,400 seconds of atomic time about 1.88 centuries ago (i.e. the 188 year difference between 2008 and 1820).  That is, the length of the mean solar day is at present about 86,400.002 seconds instead of exactly 86,400 seconds.  Over the course of one year, the difference accumulates to almost one second, which is compensated by the insertion of a leap second into the scale of UTC with a current regularity of a little less than once per year.  Other factors also affect the Earth, some in unpredictable ways, so that it is necessary to monitor the Earth’s rotation continuously.”

Earth’s Day is Getting Longer


Did you know that Earth’s day is getting longer? A tiny bit each year, to be sure, but it’s definitely getting longer and longer for Earth to rotate 360 degrees on its axis.

The Scientific American Magizine has posted an article entitled, “Fact or Fiction: The Days (and Nights) Are Getting Longer” at http://www.scientificamerican.com/article/earth-rotation-summer-solstice/. In this excerpt, NASA explains why.

“ Almost imperceptibly, however, Earth’s day–night cycle—one rotation on its axis—is growing longer year by year, and has been for most of the planet’s history.
“Forces from afar conspire to put the brakes on our spinning world—ocean tides generated by both the moon and sun’s gravity add 1.7 milliseconds to the length of a day each century, although that figure changes on geologic timescales. The moon is slowly spiraling away from Earth as it drives day-stretching tides, a phenomenon recorded in rocks and fossils that provides clues to the satellite’s origin and ultimate fate.”

Although “global warming is expected to shorten the day by 0.12 millisecond over the next two centuries by heating the oceans and changing the distribution of its mass,” clearly the effect of lunar and solar tides is greater by an order of magnitude (at least ten times the effect of global warming).

Today’s daylength

At timeanddate.com, http://www.timeanddate.com/time/earth-rotation.html,

we find that:

“Date: Friday, September 2, 2016
24 hours, 0 minutes, 0.0008836 seconds (0.8836 milliseconds)
This day will be 0.0008836 seconds longer than 24 hours. This is the time it takes Earth to rotate 41.10 cm (16.18 in), as measured at the equator.”

So, on this date the day will be about 0.9 milliseconds longer than 24 hours.

How about calendars?

What about our calendars? The Kanayama Megaliths Solar Calendar will not be affected at all. Why? Because it is an observational calendar. it will always reflect what the sun’s path tells us. Leap years will always be known through the leap-year observations in Iwaya-Iwakage. This is the beauty of the Kanayama Megaliths Solar Calendar. It is and will always be correct.


Hi-no-Michi Calendar of Kanayama Megaliths

Six-season chart

Kanayama Megaliths and Observational Astronomy

Spotko 05 25DSC03734_388DSC01101

The Kanayama Megaliths are a set of three megalithic groups in Kanayama, Gifu Prefecture. They have only within the last twenty years been found to be a solar observatory for ascertaining the calendar of the tropical year. They determine the year so exceedingly well that their calendar is the most accurate in the world today. This calendar and this observatory have been in operation for five thousand years! Or more. 

Solar Calendar

The solar calendar incorporates the four-year leap-year cycle and the 128-year leap-year cycle. How does it do so with only solar observations? Aren’t most megalithic sites an arrangement of megaliths with alignments to the equinoxes and the solstices? Why are not the other sites in the world as accurate as the Kanayama Megaliths?

The answer lies in the theory and the practice of the Kanayama Megaliths. Even though we know that the sun rises due east on the equinoxes of spring and autumn, how do we determine exactly those dates? How do we determine the dates of the summer and winter solstices? Solstice dates are notoriously hard to determine due to the nature of solstice: the time when the “sun stands still.” In other words, the track of the sun in the sky varies very little from day to day around the time of winter or summer solstice.

The way around this is to take accurate measurements. How do you do that? You use the technique of measuring spotlight positions as functions of time.

2012dec_02     DSC02342     DSC00480 (1)

Spotlight observations.  The megaliths of Kanayama were designed and constructed so as to form two chambers of stone, called Senkoku-ishi and Iwaya-Iwakage. The megaliths forming each chamber were arranged to form a small opening where sunlight could enter. The entering sunlight would form a beam like a spotlight on an interior surface such as a flat stone or the floor of the man-made cave.

Hi no Michi

Daily the sun travels its path in the sky. It is called Hi no michi, a term which comes to us from long ago. In those days, Hi, the sun was highly respected. We thoughtlessly call indigenous people, “sun worshippers.” This is highly disrespectful to our ancestors who realized the importance of the sun as the giver of life. Even though we are speaking of the path of the sun in the sky, the term Hi may have really meant the Spirit of the sun, the life-giving energy of the sun. Remember that the word, michi, means literally “path” but the connotation is “proper path” or even “law.”

The modern term is taiyou no michi, where taiyou is the physical sun. Both expressions are used today, taiyou no michi being more technical and hi no michi more poetic.

Sun’s Path in the Sky.  The sun moves through a band in the sky. The northernmost limit of this band is the path traveled by the sun on summer solstice day. The southernmost limit is the path on the winter solstice. In the middle is the path of the equinox sun. This diagram shows the three paths during the half year it takes to go from summer solstice to winter solstice or vice versa. They divide the sun’s band into two sub-bands.


Yontobun of Kanayama Megaliths

Yontobun means “dividing into four parts.” The band of the sun’s path is divided into four parts, four unique periods of the year for making special observations of spotlights. The above two periods are divided — in the sky — into two equal parts each, making a total of four periods of the year. Those four periods are not all of equal duration.

Think of the year as having about 360 days. This is a good approximation to work with. After all, we divide the circle into 360 parts called “degrees.” Mathematically, the number 360 divides easily into four parts of ninety each, and six parts of sixty each. Agreed?

Sun’s elevation angle. There’s one thing you need to know about how the sun in the sky appears to us on earth. Its elevation angle in the sky varies over the year. It is described by a sine function which looks like this.

sine function

Why does the sun behave like this? That is just the way it is! It can be explained by physics and mathematics, and the sine graph is the result. If we take the highest peak to be the summer solstice day, the lowest valley is winter solstice day. The horizontal axis represents days and the vertical axis is the number of degrees above or below the norm at the equinoxes. The curve begins with spring equinox, then summer solstice at the peak, autumn equinox at the axis, and winter solstice at the minimum, ending with spring equinox once again.

Now, this is the crucial question. When will  the sun in the sky have an elevation angle that is halfway between the summer solstice and equinox elevations, and when halfway between equinox and winter solstice elevations? Look carefully at the chart. The answer, both mathematically and observationally, is sixty days before and after the solstices, and thirty days before and after the equinoxes. Think about it.

This fact seems to be little known amongst modern people who are not very good at observing nature (or at mathematics). People ordinarily divide the year into four equal parts by counting days: about 90 for each season, and divide each season into halves of 45 days. That’s fine if the objective is to divide by days. However, in Kanayama, the megaliths are designed to divide the sun’s path by angle in the sky. Aren’t they clever?

Yontobun is the basis of this unusual solar calendar and it is made possible by accurate spotlight observations.

Perhaps the ancient astronomers of Iwaya Valley had to be extra clever because they were challenged by being in a mountainous region!

The Kanayama Six-Season Year

The yontobun cycle of the year can be described as having six parts of sixty days each. This makes for a beautiful calendar of the year, as our chart shows. Observations at Kanayama Megaliths follow the six-season pattern. Starting with winter solstice at the bottom of the circular chart, we give the beginning dates for the sixty-day seasons for observations.

12/22  Late Winter

2/19  Spring

4/22  Early Summer

6/21  Late Summer

8/20  Autumn

10/23  Early Winter

Six-season chart

Kanayama Six-Season Calendar

(by Shiho Tokuda)

The spring equinox lies in the middle of the spring season, and the autumn equinox is in the middle of the autumn season. Summer solstice occurs between early and late summer, and winter solstice occurs between early and late winter.

Leap years.  The careful astronomer sees a slip in the solar events as the years roll by, and knows to add a day every four years to keep them on track. Furthermore, it is necessary to not add a day every 128 years (every 32nd leap year). These leap-year events are observed at Iwaya-Iwakage. Leap-year observations make this the most accurate operating calendar system in the world!


日抱宮 Hidaki no Miya in 丹生川 Nyuukawa

The Land of Hida

Iwaya-Iwakage of the Kanayama Megaliths lies in the land of Hida, which is very old and mysterious. We are posting some articles to acquaint you with Hida. There was an ancient practice in Hida called Hidaki no Mitama-shizume. This may be the origin of the name, Hida.

Nyuukawa.  It was a lovely day in November when three of us started out from Takayama east to  丹生川 Nyuukawa on the road to Norikuradake. From our Hida roots study, and our Hida Koku posts, we knew that the original settlers of Hida began living around Mt. Norikuradake and spread to valleys such as Nyuukawa. The Hida people practiced a meditation known as Hidaki no Mitama-shizume, calming the spirit by embracing the sun. We learned from Yamamoto’s book that there are 19 Hidaki no miyas, shrines marking the places where Hidaki took place. We were looking for them.

Our first stop was a shrine off the main road but it did not seem likely to us, since it was on a hill with no flat space for meditating around a pond. We tried again. By asking around, we were directed to a public school where we parked, for fortunately school was out at the time, mid-afternoon. A bit early for getting out of school, we thought. The first thing we noticed was the fenced area under the sugi – a good sign! There was a totally red maple in the corner of the schoolyard. You can see part of the shrine behind it.

Shiro-i Jinja.  We made our way around toward the street. Yes, the nameplate on the haiden said, 日抱宮 Hidakimiya! Through an opening in the front, we could see inside. There were two guardians flanking the altar. The largest sugi indicated a venerable age, and was wrapping its roots around the large boulders. One of the boulders showed ancient tool marks.

There is a view of the Hida mountains to the northwest. This interesting shrine is slightly above street level.

Looking around the grounds, we felt that there could have been a place for sitting around a pond to meditate, and there was evidence of a well. The place name is, after all, 白井 “shiro-i” which means white spring.

This shrine is on the northern bank of the river, and has a nice southern exposure. In fact, it faces the direction of the winter setting sun. There is also a view of the rising sun in summer. See the map for the location of the 白井日抱宮 Shiroi Hidaki-no-miya, the fourth shrine on the northern bank below the mountains on the west. And notice that the river valley has a very favorable axis that lies on the solstice line from summer solstice sunrise to winter solstice sunset.

About nyu

Now, what is  丹生 nyu as in Nyuukawa  丹生川 ?  The first kanji  丹 is read “ni” or “tan” which means red. The first two kanji together 丹生 are read “nyu” which means a place where red is obtained, i.e., where 水銀 suigin mercury is obtained for making 朱色  shuiro vermillion paint. 辰沙 shinsha (HgS cinnabar), an ore of mercury, is found in red sand. In the Yayoi period, shinsha began to be used to avoid insects in stone coffins, for medicine, and for red lacquer. Kokougan granite is also associated with suigin. A commercial method for obtaining HgS for making vermillion was developed by the Buddhist monk Kukai after his trip to China in 806. He became rich enough to build the temples at Koyasan. Thus there is a link between Hida and Koyasan.


Summer Solstice 2016


Looking toward rising sun from inside lower grotto of Senkoku-ishi.

All photos are copyright of Shiho Tokuda, 2016.

Kanayama Megaliths made its latest post about summer solstice on June 27. You can find it here on the blogsite,  http://blog.livedoor.jp/kanayama_tour-kanayamamegaliths/archives/1058824709.htmlSince it is written in Japanese, we asked Shiho Tokuda for permission to show you some of her photos with our brief explanations. 


Summer solstice arrived at Kanayama Megaliths on June 22, 2016. Three days before, namely June 19, sun rose around 5:40 from the mountains behind clouds. Although its light could be seen between the two megaliths, the sun barely lit a dim path between them (left photo).

The Senkoku-ishi site for summer solstice observations is seen in the early hazy light (above right). By 6:30 the clouds had moved away and sunlight cast a shadow of one megalith upon another (lower right). Note that in the lower right corner of the photo, sun is shining on the entrance to the lower grotto, and here’s a close-up (below). Normally, since this is the rainy season, the floor of the grotto would be filled with rainwater. Fortunately this year, it was dry.


June 22, summer solstice day. The day dawned bright and clear. At 11:40 in the upper grotto, the beam of sunlight reached the floor and cast a beautiful oval spotlight. The shape, as usual, matched the shape carved on the outside of the megalith.

Summer solstice arrived 31 days after the dashed spotlight! The Kanayama Megaliths solar calendar still works!


This upper grotto is the same observation location as for the dashed spotlight of May 21 which we reported upon earlier. You can see the triangular stone at the top of the photo.

The large photo at the top of this page shows how the rising sun looks from inside the lower grotto.



Norikuradake 乗鞍岳 in Hida Mountains

The Hida Mountains (飛騨山脈 Hida Sanmyaku, Hida mounain range), or Northern Alps, extend through Nagano, Gifu, Toyama, and partially into Niigata  prefectures. Its length is 105km or 65 miles.

Norikuradake (乗鞍岳), or Mt. Norikura, plays a chief role in the story of Hida, as we have seen in the previous posts. Norikuradake at the southern part of the Hida Mountains is the third tallest volcano in Japan. Norikuradake’s name means “riding saddle” because of its shape.

The above photo from a postcard is a view to the east from Takayama. It shows the Hida Mountains, with northern part on top and Norikuradake, the southern part, on the bottom. The peaks and a plateau are labelled as follows. Take (dake in compounds) means peak; mine also means peak; taira means plateau. The coordinates are approximately 36 N 137 E.

Hida Mountains, top left to right (north to south):

双六岳 Sugoroku-dake (Sugoroku-game peak) 2860m
笠ヶ岳 Kasaga-take (Umbrella peak) 2898m
槍ヶ岳 Yariga-take (Spear peak) 3180m
大喰岳 O-bami-dake (Devour peak) 3101m
中岳 Naka-dake (Middle peak) 3084m
南岳 Minami-dake (south peak) 3033m
北穂高岳 Kita-Hotaka-dake  3106m
涸沢岳 Karesawa-dake (Dry valley peak) 3110m
奥穂高岳 Oku-Hotaka-dake 3190m
前穂高岳 Mae-Hotaka-dake  3090m

Norikuradake(乗鞍岳)is seen on the bottom half of the postcard. Its tallest peak is Kenga-mine. The labels are, left to right:

畳平 Tatami-daira 2700m
剣ヶ峰 Kenga-mine (Sword peak) 3026m
大日岳 Dainichi-dake (Dainichi is Buddhist deity)   3014m

This list of names, in Romaji and English, was graciously provided by Hitoshi Uchiyama.


Hida Koku Part 6. Jomon Pyramids and Rituals


Himurogatake, Kyoto (c) 2013



Kuromantayama (c) 2011


The information below on pyramid mountains and pyramid rituals is from:  http://www.geocities.jp/mb1527/N3-01-1hidakoku.html.


日本ピラミッド  Pyramids of Japan

In Hinomoto (old name for Japan) there are mountains that are said to be pyramids. Among them, on and around mountains, are 岩石祭祀遺構 boulder ritual remains. Fourteen of these pyramid mountains (and prefectures) are listed here.

大石神 Ooishigami(青森県 Aomori)・黒又山 Kuromantayama(秋田県 Akita)・

五葉山 Goyouzan(岩手県 Iwate)・千貫森 Sengenmori(福島県 Fukushima)・

尖山 Togariyama(富山県 Toyama)・位山 Kuraiyama(岐阜県 Gifu)・

石巻山 Ishinomakiyama(愛知県 Aichi)・東谷山 Tougokusan(愛知県 Aichi)・

三上山 Mikamiyama(滋賀県 Shiga)・三輪山 Miwayama(奈良県 Nara)・

日室ヶ嶽 Himurogatake(京都府 Kyoto)・葦嶽山 Ashitakeyama(広島県 Hiroshima)・

弥山 Misenyama(広島県 Hiroshima)・野貝原山 Nogaiharayama(広島県 Hiroshima)

[An annotated list of the above 14 pyramids and prefectures follows, not presented here. Then the text continues as below.]

To Hida from 越中国 Etchu province were conveyed many traditions that differ completely from other regions. These lore may seem to be occult as not many are in the academic tradition. However, they were spread from the nucleus of the region. Let us consider whether there is something here to become the nucleus, without being negative at the beginning.

ピラミッドは縄文祭祀   Jomon pyramid ritual

The center of the ritual is a pyramid. The Japanese pyramid is a mountain whose nature was modified by arranging the boulders; it is believed to have been used in sun rituals. There are many pyramids in East Japan where there are Jomon ruins in the vicinity. It is thought that these represent rituals of Jomon people. The Hida hidaki no mitama shizume ritual of Takaamahara is part of a sun faith. It was active at the time of Nigihayahi-no-Mikoto until the Yayoi era. Although he unified the Tokai and Kanto regions, they are a coastal area, whereas usually Jomon ruins are found close to mountains. Mononobe clan were settlers from along the Osaka Bay who made Yayoi settlements near the coast, and segregated from the Jomon people. Then they began to mix peacefully without friction.

However, that was not the case in inland areas. Jomon people made their sun faith using megalithic pyramids, so when Yayoi people tried to enter their land, friction arose. Shinano province struggled during the unification. Hida province is also a mountainous area and farming area is limited. The Jomon of Hida did not easily accept the unification.

Hida Takaamahara is believed in the lore to be the oldest dynasty in Japan. It can be argued that the Jomon people made a country in Hida. The Jomon people had flourished along Nyukawa with Norikuradake as their symbol. Because of climate change, they moved closer to Kuraiyama. The Jomon nation lasted for over two thousand years. Their stories became legends in Takenouchi and Hotsuma documents.

Hida is still a region where many have inherited the blood of Jomon. Jomon people were living in the mainstream, then the Yayoi people entered. The Jomon did not have any people referred to as king. However there were leaders in Hida that were called 上方様 Uakatasama, who probably led rituals mainly in the Jinzu river basin.

When did the Hida kingdom exist? It is completely unknown. It has been reported that the center moved, due to climate change, from around Norikura to around Kuraiyama. Since the great climate change for Jomon is about 4500 years ago, it may have been around that time. In the Takenouchi document there has been a Ugaya dynasty of 72 generations before Jimmu Tenno. In the Kuki document there has been a 1200 year history of 72 generations. Ugaya may have been written down in place of the Hida dynasty. As more and more people flowed in during the Yayoi era, the Hida people faced confrontation.



Hida Koku Part 5. Takenouchi Documents


Koso Kotai Jingu in Ibaraki, from http://www.kousokoutaijingu.or.jp/

In the Part 4 post,  https://iwakage.wordpress.com/2016/06/24/308/,  the history of Hida in the 竹内文書 Takenouchi documents was not presented.竹内 can be read Takenouchi or Takeuchi. We now give a brief summary of pertinent points from that part of the source article, http://www.geocities.jp/mb1527/N3-01-1hidakoku.html.


History of Hida Takaamahara According to Takenouchi Documents

There was a coup d’etat during the reign of Emperor Buretsu. He was forced to hand over documents conveying the tradition of ancient Japan. To protect this literature, he secretly allowed it to go to Etchu Toyama. The old documents were transmitted to the Koso Kotai Jingu there, whose descendants are the house of Takeuchi. The ancient documents are written in jindai moji, script of the age of kami. They referred to the documents as 「御神宝」sacred treasure. Collectively the documents are the 竹内文書 Takenouchi documents or the Takenouchi literature.

There was a government trial during the time of World War II in which documents were submitted. Although there was acquittal, the submitted documents were not returned immediately and originals were destroyed by air raids.

In the Takenouchi literature, prior to Emperor Jimmu there were 72 generations of Sumera Mikoto. An ultra-ancient Japanese archipelago was the center of politics and culture in the world. And the center of it was a governance headquarters of the Hida-Norikura Takaamahara around the Jinzugawa in Toyama.