Category Archives: Hida

Watersheds and River Systems of Hida


Watersheds of Gifu

Rivers of Hida

Our previous post was about the meeting of the Maze and Hida Rivers in Kanayama. The river systems of Hida are very interesting since they are in the central part of the island of Honshu. Thus there are rivers flowing to the north to the Sea of Japan, and south to the Pacific.

Maze River.  The Maze River (馬瀬川, Maze-gawa) begins further south and west than the Hida. It flows through Gero-shi and into the Hida River at Kanayama. Photo below, left.

Map of Gifu (above)

The watershed areas of the Gifu river systems are shown in the map of Gifu-ken. Gifu’s neighbors on the west are Toyama, Ishikawa, Fukui, and Shiga, and Mie in the southwest. On the east, Gifu is bordered by Nagano with Aichi at the bottom right, the southeast.

Major Watersheds of Gifu

Watershed is written:  流域  ryuu-iki.  The large watersheds systems are as follows. The upper left and right on the map:

庄川  Shou-gawa,
神通川  Jinzu-gawa also called  宮川 Miya-gawa
These river systems drain into Toyama Bay. The three large systems in the middle, from the left:
揖斐川  Ibi-gawa,
長良川  Nagara-gawa,
木曽川  Kiso-gawa+飛騨川  Hida-gawa
Below them is
木曽川  Kiso-gawa
and two others. Since the Maze-gawa flows into the Hida-gawa and the Hida-gawa in turn into the Kiso-gawa, these rivers all drain into the Pacific Ocean at Ise Bay near the city of Nagoya.

dsc04138-whirlpoolflowing through Nagano, Gifu, Aichi, and Mie prefectures. It is the main river of the Kiso Three Rivers together with the Ibi-gawa and Nagara-gawa. In our post at Yamanomiya, we showed the whirlpool in the Kiso-gawa at Kawakami Jinja in Yaotsu town in Minokamo (photo at left).

Iwaya Dam.  The Iwaya Dam, indicated in redIwayaDam in the center of the map, is located very close to the Kanayama Megaliths. Note the Maze-gawa flowing south from the dam to the town of Kanayama where it joins with the Hida-gawa from the northeast.
Jinzu-Miya River.  The Miya River (宮川 Miya-gawa) flows from Gifu-ken northward to Toyama-ken. When it reaches Toyama, it is called Jinzū River (神通川 Jinzū-gawa). It is 120 km (75 mi) in length and has a watershed of 2,720 km2 (1,050 sq mi). Both of these river names, the Miya (shrine) and the Jinzu (movement of kami), are respectful of the kami of rivers.
The Divide.  A watershed divide is called bunsui rei  分水嶺. Where is the divide of central Honshu? Hint: logic tells us that it would be located at the intersection of the four large watersheds, to the northwest of the Iwaya Dam. We will have more in a later post.

Snapshots of Kanayama: Where the Maze and Hida Rivers meet

2017-06-24 11.55.07 confluence

It is a thrill to stand at the power spot where two rivers meet. In Kanayama, the Hida River in the east, and the Maze River in the west join to continue their journey to the Pacific Ocean. First, here are some photos taken on the town side. The plaque reads: Maze-gawa, Maze River. It seems to translate into the Rapids of the Horse. I don’t know if it really means that. Nevertheless, the name reflects the rapids of the swift mountain stream. Those large leaves in the photo on the right are the hoba, used widely in Hida cuisine, such as the hoba sushi and hoba miso.

Looking at the Maze River from the bridge, this is what I saw. Upstream is to our left and downstream to the right.

At the end of the bridge, there is a small roadside shrine.

I made my way back to the town side of the Maze and followed the river south. Hydrangeas of different colors were in bloom.

It is the season for fishing for ayu, the delectable fish of clear mountain streams. Hida folks are very proud of their ayu.

DSC04038 Ayu fishing

I took the bridge to cross over to the east bank. South of this bridge is Mino which is not a part of Hida, geographically or culturally.

DSC04040 bridge over Hida-gawa

A view from the bridge, near the east side. Kanayama town continues on the other side of the river. After walking a few blocks right and left, I came to the Hidakanayama Train Station which you’ve seen in the earlier post. I’ve shown you a lot of photos of the river. I hope you enjoyed the beauty and serenity of the rivers that run through Kanayama.

2017-06-24 11.55.55



Snapshots of Kanayama: Foods

2017-06-22 18.58.35 HobaMiso

Hida Kanayama is a food lover’s paradise. Not only are there fresh seasonal produce deliciously served, there are local specialties as well. Let us show you some of them.

First we introduce you to hoba miso with Hida gyu (Hida beef). Hida gyu is wonderfully marbled and sooo tender! Above we see Hida gyu on a grill plate heated by a sterno burner (which conveniently goes out when the food is about done). It is served with green onions, piman peppers, and mushrooms, with the2017-06-22 19.04.04 Hoba gyu sushifamous hoba miso of Hida. Here is one of the Hida gyu nigiri sushi as served in the restaurant of Karen.Having one of these sushi is heavenly! They come two on a plate, doubly heavenly.

Of course, we must have hoba sushi, a specialty of the area. Here is what it looks like. It is wrapped in a fresh green hoba leaf that grows abundantly in Kanayama. It is delicious the first day, and possibly even better the second day. In case you are wondering, a hoba leaf is a type of very large camellia leaf.

2017-06-28 13.32.42 hoba sushi

Restaurant Hizan レストランひざん offers many popular meals. Look at the lunch you can have for only 1000 yen! And on Tuesdays and Wednesdays, Hizan serves the Japanese breakfast called morning service including egg, toast, and more for the price of a cup of coffee!

DSC04054 Hizan lunch menu

DSC04055 Hizan morning service





Kimi no Na Wa (the Movie Your Name) and the Land of Hida

Posters of Hida Kanayama by Shiho Tokuda

The Movie Kimi no Na wa (君の名は)

Did you know that the block-buster move, Your Name, takes place in Hida as well as in Tokyo? Not only is it a terrific movie, it is highly relevant to followers of this Iwakage blogsite about Kanayama Megaliths and Hida Kanayama.

Hida Furukawa is the real-life name of the movie town of Itomori where Mitsuha lives with her sister and grandmother. Through life in Itomori, we learn about traditional culture, shrine rituals and festivals. We eventually come to realize the deeper meaning of the movie. We discussed some this on the Okunomichi blogsite.

There are many hits when you search on keywords from the movie. You can easily find the places in Tokyo where the scenes in the movie take place. With a little more effort, you’ll learn the places in Hida that are depicted. People are talking about pilgrimages to these places in Hida.

May I suggest a mini-pilgrimage to the Kanayama Megaliths?

Now, let’s point out some scenes from the movie that are relevant when visiting Hida and Kanayama.

Hida Kanayama Train Station

If you take the Hida Wide-View express train to Hida Kanayama station, you already know how quaint the station is. There is the station-master’s room (and sometimes he’s not even there when you arrive). There are only two tracks, one going north and the other south. There is a covered overpass with stairs at each end (no elevator) to cross over the tracks. The train station in the movie is modeled after the Furukawa station. It looks almost exactly like the Hida Kanayama station!

Posters of Kanayama

Inside the waiting room of the Hida Kanayama station, there are some very large posters showing the beautiful vistas of Kanayama and the Kanayama Megaliths. These are the creations of our very own Shiho Tokuda. You can see three of her posters at the top of the earlier post.  And here they are again. There is a scene in the movie where Taki’s friends are in the lobby discussing the trip to Itomori. In the background behind Miki Okudera and Tsukasa can be seen the bottom halves of posters. The posters resemble, but are not the same as Kanayama Megaliths, the waterfalls, and the kinkotsu walking tour of Kanayama.   

The Megalith

The goshintai of Grandmother’s shrine is the megalith in the center of the meteor crater. Mitsuha goes there with Grandmother and leaves the kuchikamizake there in the iwaya cavern of the megalith. Later, Taki enters the cavern and finds the sake. Not all megalithic structures in Japan have caverns, so this is unusual. Although the megalith in the movie does not physically resemble the Iwaya-Iwakage of the Kanayama Megaliths, I felt that they were still very similar to each other. If you have been inside the Iwaya-Iwakage, you may have the same feeling of sanctity and mystery.


Photo of Myoken Shrine in the cavern of Iwaya-Iwakage

I can’t help but feel that Makoto Shinkai, before making the movie, went to Kanayama and visited the Kanayama Megaliths. He has a deep sense of the nature of the land of Hida. Why don’t you come and discover Hida Kanayama for yourself?




Visiting Kanayama Megaliths in Hida-Kanayama


Hello Fans of Kanayama Megaliths:

We have been communicating with you about Iwaya-Iwakage and the megaliths of the Kanayama Megaliths System for nearly two years, since June 2015. During this time, we have explained the intricacies of the observational methods employed here, and have presented our super-accurate solar calendar. We have shared our photos of the solar light phenomena at the three sites at different times of the year. Especially exciting to us was our trek up the Higashinoyama to view the winter solstice sunrise. And we recently posted the oval spotlight in Iwaya-Iwakage on spring equinox day.

Iwaya Valley Three Sites

The three sites of Kanayama Megaliths in Iwaya Valley. As you know, the system consists of three groupings, at three sites, near the Iwaya Dam. The Kanayama Megaliths complex is so fascinating and rich with things to discover that you may want to spend more than a day visiting us. This is a lovely forested area in the mountains of Hida with fresh air and clear streams — and waterfalls! Increasing numbers of visitors have been coming to the Megaliths, to the quaint town of Kanayama, and to this blogsite. So we thought we’d provide updated information about visiting us. This Google map shows the forested region around Kanayama.  Sometimes, the town is called Hida-Kanayama, Kanayama in Hida, or Hidakanayama

  • Where are the Kanayama Megaliths located?

Gero City.  The Kanayama Megaliths are located in the mountains of Hida, in Kanayama Town, city of Gero. The city of Gero is in the middle of Gifu Prefecture. The lower arrow in this map of Gero-shi points to Kanayama, the upper arrow to the Megaliths. The Kanayama Megaliths website gives location information here

KY map

Gifu Prefecture and Hida.  In the map at the top of this page, Gifu Prefecture is the green area. As you can see, Gifu Prefecture lies to the north of the city of Nagoya, the third largest city in Japan and the capitol of Aichi Prefecture. The part of Gifu Prefecture from Hidakanayama north to the top of the map is traditionally called Hida, an ancient and somewhat mysterious place. The towns of Hida-Takayama and Shirakawa-go are well known internationally.

Chubu.  Gifu is a prefecture in the region called Chubu. Although you may not be familiar with the name Chubu, it means literally, “central part,” and it refers to the central region of the main Japanese island of Honshu, namely Central Japan. It is officially made up of nine prefectures. Gifu Prefecture is shown left of center in this Wikimedia Chubu map in lime green. The Hida mountains, the “Northern Japanese Alps,” separate Gifu from Nagano Prefecture to its east.

Japan_Chubu_Map M

By Kambayashi (Own work) [CC BY-SA 3.0 (, via Wikimedia Commons

  • How do I get to Hida Kanayama in Chubu?

By Air.  Please refer to the above Kanayama Megaliths link for detailed information on getting to Kanayama by air from Osaka and Tokyo. The closest airport has the code name NGO. In Japan, it is called Centrair or Chubu and is actually located in Tokoname city. To Westerners, we know it as Nagoya Airport. The Kansai International Airport, KIX, is in Osaka. The Narita International Airport, NRT, and Haneda International Airport, HND, serve Tokyo. Whether by air or by train, we suggest that you make your way to Nagoya Station in the city of Nagoya, Aichi Prefecture.


Access map.  The access map at the top of this page shows the routes from Nagoya and from Takayama 高山 to Hidakanayama and the Kanayama Megaliths by train and by highway.

By train.  We suggest you come by way of Nagoya Station. There, you catch the Hida Wide-View express train on the Takayama line that is headed north to Takayama. It will take you to Hidakanayama station in a mere 90 minutes. There are only a few Wide-Views per day, so plan accordingly. The train route (bold dashed line) goes from Nagoya north to Kanayama and beyond. You can see that it parallels Route 41. The route and timetable website,, is very useful. Be sure to enter the  name of the station as HIDAKANAYAMA. Look for the routes of the Hida Wide-View. It’s a good idea to stick to express trains, direct routes, and major cities.

By car.  To drive to Kanayama from Nagoya, take Route 41 north-north-east. It will take you right into town. Driving time is about 1 hour 45 minutes.

  • How do I get to Kanayama Megaliths from Kanayama Town?

The Kanayama Megaliths are, of course, not in town but rather in the mountains. You can get to the megaliths from town in about half an hour by car. A taxi is available for hire, with a special fare for megalith visitors. Head north from town, taking the left fork, Route 256. You will be headed for Iwaya Dam. When you come to the fork, take the right on to Route 86. Stay on Route 86 as it curves around. As you come down the bend into Iwaya Valley, slow down since the entrance to the megaliths will be on your left, a hard left. 

VISIT KANAYAMA.002 LWhen driving from Nagoya directly to Kanayama Megaliths, you have two choices:

  1. Nagoya —(国道 Route 41号)—Kanayama— (国道 Route 256号)—(県道 Route 86号)—Kanayama Megaliths
  1. Nagoya —(国道 Route 41号)—Kanayama— (国道 Route 41号)—(ささゆりトンネル Sasayuri Tunnel)—Kanayama Megaliths

They take about the same amount of time. When taking the Sasayuri Tunnel, be sure to take the immediate left after exiting the tunnel.

When you use a mapping website or app, you might want to enter as your destination “Myoken Shrine.” That is the name of the small shrine on the site of the megaliths. Entering “Myoken Shrine” on Google Maps will give you this close-up view of the last bend. 

The above maps and information are courtesy the Kanayama Megaliths Research Center and the Kanayama Tourist Association.

What do you do when you get to Kanayama? Where do you stay? Please see our next post.


Kanayama Megalithic Solar Calendar

Kanayama Megalithic Solar Calendar

Six-season chartThe ancient people of the Japanese archipelago called their land Hinomoto (Hi-no-moto), the Essence of the Sun. The Kanayama Megaliths are located in the mountains region called Hida, the Land of the Sun. The Jomon people who constructed the Kanayama Megaliths were sun-watchers primarily and star-watchers partially. It is difficult to have a good view of the night sky when one is in a mountain forest. Instead, the Kanayama astronomers focused on acquiring careful knowledge of the movement of the sun in the sky. The Japanese term is Hinomichi (Hi-no-michi), the Path of the Sun.

The Jomon sun-watchers developed a highly sophisticated megalithic system for accurately following the Path of the Sun.

The Kanayama Megalithic Solar Calendar took into account the 365 full solar days in a solar year. Plus they included leap-day corrections on a four-year leap-year cycle as well as a longer 128-year leap-year cycle. Therefore, this calendar is supremely accurate to one day in 51,000 years. Compare this with our modern Gregorian calendar which will accrue a one-day error after only 3236 years. Since 435 years have already elapsed, there are only 2801 years left before we will encounter the one-day error. On the other hand, while the megaliths may have been functioning for 5,000 years already, they still have another 46,000 years to go.

sine function

The Kanayama Calendar is based on the Jomon’s knowledge of Simple Harmonic Motion or SHM. SHM is what describes the periodic motion of pendulums, playground swings, and the sun in the sky over the course of the year. (Hint: it is a sine function.) The solstices (solstice means the standstill of the sun) occurs at winter and summer when the sun’s noonday position in our sky seems to change little day by day. On the other hand, at time of equinoxes, spring and fall, the sun’s noontime position changes rapidly in the sky. All sunwatchers know this. They try to form their own calendars by observing the sun’s position at the two solstices (6/21 and 12/22) and the two equinoxes (3/21 and 9/23). However, it is extremely difficult to know just when the sun is at solstice, by the very fact that it doesn’t “move” much in the sky.

The half-angle dates. The Kanayama sunwatchers were highly creative. They asked themselves, “When is the sun’s noontime position half-way in direction (in angle) (in the sky) between the solstice and the next equinox?” We modern people would probably say, “Half-way between the seasons, so I would say about ~45 days after the solstice, right?” If that is your answer, you are wrong! The “half-way in the sky” date is ~60 days after the solstice, and ~30 days before the equinox.

In case you think this “half-angle date” will vary with your location (namely, latitude) on earth, you are again wrong. This date can be calculated from SHM (which is after all, just a sine function). You will calculate the two dates before and after the summer solstice as:

4/22 and 8/20


and the pair for the winter solstice as:

10/23 and 2/19.


Therefore, the solstices are bracketed and are in the midpoint of the two summer half-angle dates and the two winter half-angle dates. Observations of solar position are made on those four dates at the Kanayama Megaliths. We wonder if other astronomers in other parts of the world took special observations on those four dates.

Pinpointing the Summer Solstice.  The determination of summer solstice day is further refined 31 days before and after the solstice day. A megalithic grouping (which we call the Senkoku-Ishi) was arranged (and it still is) so that a spectacular spotlight pattern appeares on a rough panel for a few days beginning, and a few days ending, on:

5/21 and 7/22


Leap-year Determination.  Careful observation of the shift of the light patterns from year to year tells us that the solar year is not exactly 365 days long, that a day has to be added from time to time. Some times, though, we can expect to add a day by a four-year cycle but find that the extra day is not needed this year. That happens every 128 years. So there are, within a couple of human lifetimes, two leap-year cycles of four years and 128 years. There are higher order cycles as well, if one lives long enough.

How are the exact years for adding an extra day to be determined? Well, the Kanayama astronomers decided to make a special observation on 10/14 (if a normal year). If a leap-day is needed, the observation will extend to 10/15. This is how they would know. The “other side” of the winter solstice is 2/28. So another pair of important dates is:

10/14 and 2/28.

And so there would be a corroborating solar observation and then an extra day would be inserted the next day. How clever!

DSC00501 (1)


Green 杉玉 sugi-tama



Have you ever seen a fresh, green sugi-tama newly raised outside a sake brewery?  If you visit the blogsite of Okuhida Sake Brewery,, you will see this photo. Better yet, go to Hida Kanayama and visit the Okuhida Brewery.

杉玉 sugi-tama is a 玉 tama, ball made of 杉sugi, Japanese cedar (Cryptomeria japonica). It is a sign that new sake has been created. The 杉玉 was raised at 10 am on December 2 with a sake-tasting event. Congratulations for another good year of premium sake!

Our previous posts about Okuhida Sake include:

Since many of us have never seen the sugi which rarely grows outside of Japan, here is a photo taken in Iwaya Valley near the  Kanayama Megaliths.