Eternal History told through Iwami’s Volcanoes
Trip of Discovery to the “Jomon Forest” and “Silver Mine”

Japan Heritage Oda City

STORY

MA P

Sanbe Volcano (Lava)
Lava that erupted approximately 16,000 to 4,000 years ago

7KH6LOLFLƂHG:RRG
of Hanenishi

Tategamiiwa
Rock

Tagi Sta.

Sanbe Volcano (Pyroclastic rock)Volcanic ash, lapilli, and pumice that erupted approximately 70,000 to 4,000 years ago

Mt. Oetakayama volcano (Lava, pyroclastic rock)

Michi-no-Eki“Road Ginzan”

Sea of Japan

Lava, volcanic ash, pumice, etc. that erupted approximately
2 million to 700,000 years ago

R
 J



Tsunozu Formation

Volcanic rocks, pyroclastic rocks, and sedimentary rocks
formed around 15 million years ago

Shizunoiwaya Cave

Isotake Sta.

the MAP No.

nSa
Oda-chuoSanbesan IC

Shizuma-cho

7KH6LOLFLƂHG
Wood of NimaIsotake-cho

Izumo City

Kute-cho
Mt. Yogaisan(299m)

Oda-choTomiyama-choSanbe Azukihara Buried Forest Park



Nima
Sta.

NimaIwamiginzan IC

Kotogahama Beach

Maji Sta.

Oda-Asayama IC

Odashi Sta.

Shizuma Sta.

Oya-cho(Sanbe Jomon no Mori Museum)

Sanbe Azukihara Buried Forest
Arareishi Production areaof Matsushiro Mine

Mononobe Shrine

Yamaguchi-cho

Kuri-cho









Sanbe-choNima-cho Mt. Ryugan (Tatsuiwa Rock)Ogasawara-style
musical rice planting

375

Mt. Kigamiyama(411m)

Yunotsu Sta.
IwamiFukumitsu
Sta.

YunotsuIC*XBNJGVLVNJUTV*$

Hamada/Masuda

Mt. Takayama(499m)

Yusato IC

Mt. Yogaisan(414m)

Omoricho

Pastoral scenery of
Mt. Sanbe

Omori Ginzan Area
(Townscape of Omori)

Mt. Tsurubusan(538m)

Iwami Ginzan
World Heritage Center

Ukinunonoike
Pond

Mt. Sanbe






Mt. Taiheizan(854m)

Sadame Pine TreeMt. Oetakayama
volcano

Mt. Hikageyama(718m)



Mt. Magosanbe(903m)

Fukumitsuishi Stone quarry

Mt. Osanbe(1126m)
Mt. Mesanbe(957m)



Mt. Kosanbe(961m)(587m)

Sahimeyama Shrine
and Tane KaguraIwami Ginzan Silver Mine Ruins.U4FOOPZBNB (Sennoyama-no Fukuishi deposit) Minakami-cho
N
Mt. Yatakijozan(634m)

Yunotsu-cho Mt. MitsugoyamaMt. Moritayama(664m)

Kawai-choYusatoSta.

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*[VNP

cho

Oniiwa Rock of Onimura

Michi-no-Eki“Goise Nima”
Nima Sand Museum

Line
Main Asayama-

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wa
ess
xpr
E
Hane-cho-in

9Torii-choSan-in Expressway

Scheduled to open in 2023.

Strata related to green tuff

Linked within the text.

Hane
Sta.

Kute Sta.

Sedimentary rocks formed approximately
3 million to 1 million years ago (with layers of porcelain clay)

-in
San

Iinancho

Sanbe Soba
Sanbe Onsen
Sanbe district area
Mt. Oetakayama(808m)

Misato-cho
Oshiro-cho

Publisher

Sojiki-cho

Oda City Japan Heritage Promotion Council(Secretariat: Within the Oda City Hall Tourism Promotion Division)

1111 Oda, Oda-cho, Oda City, Shimane, 694-0064
TEL : 0854-83-8192 FAX : 0854-82-9150 Mail : o-kankou@city.oda.lg.jp
Supervision: Tadashi Nakamura, Curator, Shimane Nature Museum of Mt. Sanbe

Oda City Japan Heritage
special website♤⾔䌑䍲倀ⵊ䌪倀ⵊ魕徎嵛氠◜噺魀鎢ⲙꓭ

https://www.iwami-kazan.jp/en/镸⩱䬹掾俠⤫◜噺

Walking to Oda City Japan Heritage Sites

CONTENTS

Jomon Forest reborn in
Ⅰ Ancientmodern times
Sanbe Azukihara Buried Forest
Mt. Sanbe

As you descend the stairs to an undergroundroom, you encounter several huge trees

Volcano that has nurtured a
Ⅱ Sanbebountiful way of life

towering in front of you. These trees fromthe Jomon period (14,000 to 300 BCE),

Pastoral scenery of Mt. Sanbe
Sanbe Soba

which were buried deep underground by theSanbe Onsen

eruption of Mt. Sanbe, have been preserved

Ukinunonoike Pond

through the ages to appear just as they were

Mononobe Shrine

so long ago. Japan is a land of volcanoes.

Sahimeyama Shrine and Tane Kagura

Although volcanic eruptions threaten theOgasawara-style musical rice planting

lives of the people, they have brought

Sadame Pine Treevarious blessings to “Iwami no Kuni Oda”

(Oda in the Iwami Province). The ore

Ⅲ



Iwami Ginzan Silver Mine site
created by a volcano

deposits of the Iwami Ginzan Silver Mine,
which once made “Cipangu ( Japan)”

Mt. Oetakayama volcano

famous around the world, were also born ofIwami Ginzan Silver Mine Ruins

the magma from those eruptions. And the(Sennoyama-no Fukuishi deposit)

bountiful land nurtured by the volcano has

Omori Silver Mine Area

enriched the lives of its inhabitants. “Iwami

Kotogahama Beach

n o Ku n i O d a” w h e r e t h e h i s t o r y o f

blessings of volcanoes that
Ⅳ The
have nurtured life

volcanoes lives on in the roots of daily life.



Arareishi Production area of Matsushiro

the land of fire awaits you.



Mine



Fukumitsuishi Stone quarry

Here, a journey of discovering the bounty of

Oniiwa Rock of Onimura
Tategamiiwa RockThe Silicified Wood of Nima
The Silicified Wood of Hanenishi
Shizunoiwaya Cave
Mt. Ryugan (Tatsuiwa Rock)

POINT

1

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Jo
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2

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thatgave birth
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Iw
Iwami
Giinzann Silver
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Sililverr Mine
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POINT

3

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About Japan Heritage
Certain things that tell the story of Japan's culture and traditions throughthe historical charm and unique characteristics of a region are recognized by
the Agency for Cultural Affairs as “Japan Heritage.” The purpose is to help
revitalize regional communities through the comprehensive community-led
development and utilization of various groups of tangible and intangible
cultural properties of great attractiveness that are indispensable for tellingsuch stories, including strategically disseminating information on thesecultural properties not only in Japan but also overseas.
02

Mt. Sanbe is a symbol of Oda City and is one of themythical mountains that appears in the Kunibiki(Land-Pulling) Myth. The peaks created by the
volcano became objects of worship, and the volcanic
ash that flowed down at the foot of the mountainpreserved a forest from the Jomon period. In addition,
the graceful scenery of the grassland was created by theactivities of the people who made good use of the
volcanic ash soil.

In the 16th century, silver from the Iwami Ginzan
Silver Mine had a great influence not only on Japan,
but also on the world during the Age of Discovery.
The driving force that allowed this mine to achieve
such historical magnificence was the “Fukuishi”(volcanic silver ore) produced by the action of the Mt.
Oetakayama volcano. The magnificence of the Iwami
Ginzan Silver Mine is also the origin of the history
and culture of Oda City.

The great crustal movement that split the edge of the
Asian continent, expanded the Sea of Japan, andformed the Japanese archipelago, was accompanied byintense volcanic activity. The green tuff that ischaracteristic of the volcanic ejecta thrown up duringthat activity is distributed widely in Oda City, giving
rise to various mineral and rock resources and a richly
varied landscape.

03

Ⅰ

A mysterious forest towering underground

Ancient Jomon Forest reborn
in modern times."1/P

During the Jomon period, when people lived off theSanbe Azukihara
Buried Forest

blessings of the mountains and the sea, the Japanese

A Jomon period forest with huge trees. The Sanbe Azukihara Buriedarchipelago was covered in forests with huge trees. There

Forest is a valuable site that gives us a view of an ancient Jomon Forest.

is a place that conveys the magnificence of those ancientThis forest lays buried under the ground for about 4000 years.

forests in the present day. The Sanbe Azukihara Buried

The excavated forest comprises mainly cedar trees, many of which are

Forest was miraculously preserved through the eruption

massive, with trunks around 2 meters thick. In the undergroundof Sanbe Volcano and several fortuitous coincidences.

exhibition room, where the site has been partly excavated, several giant

W h e n yo u l o o k u p a t t h e g i a n t t re e s t owe r i n gtrees stand, still rooted to the ground just as they were when the forest

imposingly above you, you may even feel as if you havestill lived. Even broken off as they are, the tall, straight trunks of theseslipped back in time to a primeval landscape.

Japanese cedars exceed 10 meters in height, and it is estimated that theheight of these trees when they were alive was more than 40 meters. If
you look up at the trees, you can imagine the scenery of the forest as it
would have been seen by the Jomon people. Untouched by humandevelopment, a great forest grew up here over hundreds to thousands ofyears.
The eruption of Sanbe Volcano played a role in preserving this forest to
the present. Although the trees were hit by debris and pyroclastic flows
generated by volcanic activity, thanks to a combination of
topographical coincidences, they were not knocked down or burnt up,
but were buried deep underground and miraculously preserved to thepresent day.
Sanbe Azukihara Buried Forest Park
(Sanbe Jomon no Mori Museum)〒694-0003
58-2 Tane, Sanbe-cho, Oda City, Shimane
TEL 0854-86-9500
Yes

An active volcano
where you can feel thebreath of the earth."1/P

Mt. Sanbe
Yes

Yes

Yes

Mt. Sanbe appears in the Kunibiki (Land-Pulling) Myth and is a beloved symbol of the region bothin the past and present. With its abundant fields of natural flowers, it is also known as a popularplace for observing nature, and many people come here for mountain climbing and camping.
This mountain was formed by repeated volcanic eruptions. The volcanic activity began about
100,000 years ago and continued until about 4,000 years ago. Large eruptions in the early period
created a caldera with a diameter of 4.5 km, and in subsequent eruptions from the Jomon period
onward lava erupting inside the caldera created several peaks, of which Mt. Osanbe (1126 m) is thehighest. Notable for its distinct string of peaks, each named like members of a family—man,
woman, child, grandchild—as well as for the quality of its grassy plains that spread out on the
gentle slopes at the base of the mountain, this landscape has been designated as a national park.

04

05

A lake formed by an eruption."1/P

Pasttoral sceneryy ooff N
PastoralNishinohara
iishhinoharh aⅡSanbe Volcano that has
nurtured a bountiful
way of life

Development at the base of the volcanic
land formation."1/P

Blessed with a bounty of spring water, the river that flows from Mt.

Pastoral scenery of
Mt. Sanbe

Sanbe brings rich harvests to the fields in the basin, and people

The beautiful scenery of the grassland spreads out at the foot of thehave revered and cherished the mountain as the land where the god

tightly packed cluster of peaks. Sometimes you can even see cows

of agriculture dwells. And yet, the volcanic ash soil of Mt. Sanbegrazing. The grasslands are also a treasure trove of rare flowering plants

may not have been very fertile soil. Nevertheless, the people here

such as pasque-flowers, yu-suge lilies, and Japanese gentians.

have made good use of the land for things like raising cattle and

The landscape of expansive grasslands was born from many years of

growing buckwheat. That history has led to the stunning naturalraising cattle and horses. This land of volcanic ash soil was scarce inenvironment of today.

water and could not be used for crop farming. It was the Yoshinaga
domain, established within the territory of the Iwami Ginzan Silver
Mine in the first half of the Edo period, that encouraged the use ofthis land for raising cattle and horses. The breeding of cattle,
important as a labor force for agriculture and transportation of goods,
was also an economic promotion measure. The grasslands were also
used for a time as training grounds for the former Japanese Army. The

Ukinunonoike Pond

Mt. Osanbe and Mt. Kosanbe rise above the serene water of
Ukinunonoike Pond. On days when there is no wind, a mirror imageof the mountains (called “Sakasa Sanbe”) is reflected on the surface ofthe lake. This pond that lies in the lower part of Nishinohara is anatural lake with an area of about 13.5 ha. The lake was formed byvolcanic ejecta from Sanbe Volcano blocking the exit of the valley,
and it is the source of the Shizuma River that flows into the plains of
Oda City. The lake is also important as a water source for irrigating
fields, and the Nibehime Shrine on the shore of the lake is a place ofworship for the farmers of the basin. Only a small amount of waterflows into the lake, and most of the water seems to be supplied byspring water percolating up from the bottom of the lake.
The name is said to derive from an old legend about a giant serpentand a young woman, in which the clothes of the young woman who
entered the water floated on the surface of the lake. It is also one ofthe possible sites of the “Ukinuma Pond” mentioned in
the Manyo poem by Kakinomoto no Hitomaro.
Yes

Yes

The source of Sanbe Onsen

A hot spring resort that has prospered since
the Edo period."1/P

Sanbe Onsen

Sanbe Onsen, where the light brown muddy water warms your body,
is a blessing from the heat of the volcano. From the spring source,
located between Mt. Magosanbe and Mt. Hikageyama, more than
3,000 liters of hot water gushes out every minute, the largest volumeof natural hot spring water in the Chugoku region. The spring type isa sodium-chloride spring and the spring source temperature is around
37°C. The hot water, which is colorless and transparent immediately
after it gushes out of the earth, eventually turns cloudy due to iron andother minerals. After soaking in the free-flowing hot spring water for awhile, tiny bubbles of carbon dioxide envelop your body, slowly
warming you up.
The heat source of Sanbe Onsen is magma that remains underground.
The magma is not believed to be hot enough to cause an eruption, but
it warms the groundwater that seeps down into the earthand sends it back to the surface as a hot spring.

current scenery has been formed over a long history.
Pastoral scenery of Higashinohara

Yes

Pastoral scenery of Kitanohara

Yes

The shrine of the god of literary andmartial arts, the repose of souls, and victory
Cultivation of Sanbe Highlands."1/P

Sanbe Soba."1/PSanbe Soba emits a mellow aroma as you bite into the thinly sliced noodles. The uniqueflavor that will impress even soba connoisseurs has been sustained by farmers and soba shop

Sanbe. High-quality wasabi is cultivatedusing the abundant spring water dotted

Iwami no Kuni Ichinomiya Mononobe Shrine

around the foot of the mountain.

〒694-0011
1545 Kawai, Kawai-cho, Oda City, Shimane
TEL 0854-82-0644

the Edo period.
Buckwheat can grow even in soil with poor moisture and nutrients, and because it maturesin a short period of time, it has long been actively cultivated in the Sanbe region, which has
volcanic ash soil. The dramatic temperature variation of the highland climate nurtures theflavor, and in the Meiji era, it was counted as the only soba production area in westernJapan. In 2020, it was registered as aGeographical Indication (GI) for theprotection of local products, and its national
reputation is growing once more.
Wasabi, which is an indispensable condimentin Japan, is also a special product of Mt.

06

Mononobe Shrine

Umashimaji-no-Mikoto is revered at Mononobe Shrine and it's said
to be the founding father of the Mononobe clan, a local ruling family
in the Yamato kingdom, is located in Kawai-cho, Oda City, where the
Shizuma River flowing from Mt. Sanbe joins the Oshihara River. The
shrine is majestic and has the largest Kasuga-zukuri style main shrine
structure in Japan. Along with its association with the Mononobe
clan, Mononobe Shrine also includes within its precinct the Ippeisha
Shrine, said to enshrine one of the legendary sacred bottles that gave
Mt. Sanbe its name; and thus, it is a shrine that has venerated Mt.
Sanbe since ancient times. The rice planting festival held in July
involves a ceremony in which a young girl represents Sanbaisan, thegoddess of the fields, who is invited down from Mt. Sanbe. The little
goddess Sanbaisan is also associated with Sanohime (the“Princess of Agriculture”), represented in the old name of
Mt. Sanbe, “Mt. Sahime.”owners who have carefully protected the native Sanbe variety that has been passed on since

Sanbe Soba



Yes

Yes

07

Event to pray for a good harvest."1/P

Ogasawara-style musical rice planting

The Ogasawara-style musical rice planting is a traditional folk performance of the Chugoku region that has a history dating back to the Warring States
period. It is a gorgeous performing art in which performers wear colorful costumes and play large drums, smaller hand drums, flutes, etc. It is also an
agricultural Shinto ritual to pray for a bountiful harvest. In the Mt. Sanbe region, this tradition has been handed down in the Ikeda and Koyahara
districts of Sanbe-cho, and efforts are being made to carry on the tradition at the Ikeda Elementary School, which serves both districts. At the rice
planting festival held at Mononobe Shrine in July, the rice planting musical dedication of Koyahara is performed, which reveals a part of the faith in Mt.
Sanbe, the source of water. In Oda City, the Ogasawara-style musical rice planting performance of Oshiro-cho has been designated as an intangible folk
cultural property of the city, and in Minakami-cho, the Hanataue rice planting festival has been passed down through generations.

Expressing faith in the mountain."1/P



Sahimeyama Shrine andTane Kagura

The old name of Mt. Sanbe, Mt. Sahime, is mentioned in the ancient record of Izumo Fudoki,compiled in 733, and is regarded as one of the stakes of the Kunibiki (Land-Pulling) Myth. The
mountain’s old name is still retained by Sahimeyama Shrine, located in Tane, Sanbe-cho, Oda
City. This shrine is said to have been built in 891 and is dedicated to Mt. Sanbe, which was an
object of worship in ancient times. The enshrined deities are Onamuchi-no-Mikoto,
Sukunahikona-no-Mikoto, and Suseribime-no-Mikoto. At the shrine’s annual festival andagricultural Shinto ritual Omoto festival held every seven years, the Tane Kagura performance ispresented. It is an elegant Kagura dance of the traditional Rokuchoshi (six-chord) style that has
been designated as an intangible folk cultural property of Oda City. Kagura has also gained
popularity through performances at events such as the Kagura Festival.
Sahimeyama Shrine

Tane Kagura Heritage Museum regular performance〒694-0003
305 Tane, Sanbe-cho, Oda City, Shimane〒694-0003
Tane, Sanbe-cho, Oda City, Shimane
TEL 0854-88-9950

Yes

Yes

（大田市観光協会）
Yes

08

Yes

An old pine over 400 years old."1/P

Sadame Pine Tree

Yes

Yes

If you follow the road leading to Mt. Sanbe from the west (the Mt. Sanbe Park Line), as the grassy plains ofNishinohara spread out before you, you will be greeted by an old pine tree known as the Sadame Pine Tree thathas stood there for hundreds of years. This pine tree is said to have been planted as a milestone marker during
the Iwami land survey conducted by Nagayasu Okubo, the first magistrate of the Iwami Ginzan Silver Mine.
Originally, there were two trees, one on either side of the road (the other died in 2007). Its exposed roots arewrapped around several large rocks, indicating that it was originally planted on top of a mound.
When it snows heavily, Nishinohara becomes transformed into a field of snow. In the past, when snowstorms
occurred, it was sometimes difficult for travelers to know which way to go. Thus, pine trees were planted as roadmarkers at intervals of several hundred meters, starting from the Sadame Pine Tree, and have served to watch
over travelers.
09

Ⅲ

Iwami Ginzan Silver
Mine Site created by
a volcanoIwami Ginzan Silver Mine is said to havebeen developed by Kamiya Jutei, amerchant of Hakata. From the 16th
century to the beginning of the 17th
century, the silver ore called “Fukuishi”
was the driving force behind the hugevolume of silver production at that time.
This ore was created by a volcano. The
economic power of the silver that camefrom this volcano affected not only Japanbut also East Asian and European
societies and left a great mark on world
history.

The volcano that createdIwami Ginzan Silver Mine."1/P

Mt. Oetakayama
volcanoIn springtime, Mt. Oetakayama (808 m) becomes home to
many Gifu butterflies (Japanese luehdorfia) that flit about
among the flowers, including many rare flowering mountaingrasses such as Misumisou (Hepatica) and Izumokobaimo(Fritillaria ayakoana), and this sight attracts many climbers to
the mountain. The north side of this mountain range is linedwith steep peaks, forming an eye-catching group of
mountains within the gently sloping terrain known as the
Iwami Highland. These mountains were formed by repeated
volcanic activity occurring from about 2 million years ago toabout 600,000 years ago, and are collectively known as Mt.
Oetakayama volcano. The area has a cluster of more than 30
lava domes, formed by thick lava, but only Mt. Sennoyama(537 m) is a “volcaniclastic mound” formed by theprecipitation of volcanic ash and lapilli. The Iwami Ginzan
Silver Mine is located at one corner of the peaks, and castles
were built at Mt. Yatakijozan and Mae Yataki to guard thesilver mine.

A place that prospered as a mining town."1/P

Omori Silver Mine Area

Established as a mining town for the Iwami Ginzan Silver Mine,
Omori-cho is lined with rows of houses with red roof tiles along thevalley where the Ginzan River flows. The townscape, which has thelayout of the Edo period, retains the atmosphere of the past, even as
the people conduct their modern lifestyles. In the Edo period, theOmori Magistrate's Office (Omori Daikansho) was located here, andit was the political and economic center of the Iwami Ginzan Silver
Mine territory under the direct control of the shogunate.
In addition to the Fukuishi silver ore that was formed by volcanic
activity and brought about the prosperity of the Iwami Ginzan Silver
Mine, the green tuff created by volcanoes during the formation of theJapanese archipelago was widely used as building material in thetownscape, and the stone walls and other structures made of carefully
cut stones create an orderly scene. Quarrying was carried out even
within the townscape, and the remains of those stone quarries that canstill be found in various places create a unique atmosphere.
Yes

Yes

A beach of singing sandRemnants of mine tunnels stillvisible today."1/P

Kotogahama Beach

Kotogahama Beach is a 1.4 km stretch of white “singing sand” thatmakes a sound when you step on it. The sound is produced by the
uniform grains of quartz sand rubbing against each other, but if thesand becomes dirty it will immediately stop producing the sound. So
Fukuishithe singing sand is also proof that the beach is pristine. The beach islocated in a semi-circular bay with two capes of green tuff bedrock
protruding on either side. It is thought that this shape lessens the

Iwami Ginzan Silver Mine, the source of radiance

power of the waves, so that the sand is continually washed by thewaves within the bay. Some say the bay itself may be a volcanic crater.

."1/P

Iwami Ginzan Silver Mine Ruins (Sennoyama-no Fukuishi deposit)

Full-scale development of the Iwami Ginzan Silver Mine began in the 16th century, and its mass production of silver had an impact on politics andeconomics both in Japan and overseas. As the reason for its success, the significance of the unique silver ore called “Fukuishi” cannot be overlooked.
Fukuishi is silver ore derived from rocks that were formed by the accumulation of volcanic ash and volcanic lapilli. The area where Fukuishi wasdistributed, from near the summit of Mt. Sennoyama to the eastern side of the mountain, was called the Fukuishi deposit. Fukuishi was often
distributed over large areas, and the rock itself was not particularly hard, so it could be excavated quite efficiently. The ore was a combination of minerals
that allowed the silver to be easily extracted using a smelting technique called cupellation, introduced in the 16th century. This led to the mass
production of silver from the 16th century to the first half of the 17th century.
Yes
Yes
10

Behind the beach stand rows of houses in the Maji district. The
beauty of the singing sand, which is said to be the best in Japan, hasbeen preserved by the local residents
who have cherished this beach that is
so closely connected to their lives, suchas in the holding of traditional Bon
Odori dances.
Yes

Yes

Narisuna (singing sand)11

Ⅳ

The blessings ofvolcanoes that havenurtured life

The volcanic activity that gave birth to the Japanese archipelago so very
long ago also brought Oda City a wealth of resources and a richly
varied landscape. Rocks formed from the volcanic ash that piled up
thickly after the eruptions were used as stone material in daily life, andthe trees buried in the eruption became silicified (petrified) wood.
Gypsum, of which this area was one of Japan’s largest production sites
in modern times, is yet another product of the volcanoes. The“Arareishi (aragonite) of Matsushiro Mine” imparts the memory of thetimes when the area was also a mining town.

Get to know the culture of stone."1/P

Fukumitsuishi Stone
quarryThese quarries, which were hand-dug into the rock at an angle, have ahistory that dates back to the Muromachi period (1330s—1570s), andin the underground space behind them, the Fukumitsuishi Stone
quarry continues to this day. The stone that is mined is known as green
tuff, which has a pale green tint and a warm touch. More than 15
million years ago, there was intense volcanic activity due to the crustal
movement that formed the Japanese archipelago. At that time, volcanicash, pumice, and other minerals were deposited on the seabed, creating
the stone called “Fukumitsuishi.” Soft and easy to process, it was used
for many purposes and was distributed mainly in the Iwami region. In
Iwami Ginzan Silver Mine in particular, it has been used in large
quantities for stonework such as tombstones.
In the past, tuff was quarried all over the country, but only a few
quarries are still in operation today, making Fukumitsuishi stone avaluable resource.
Fukumitsuishi Stone quarry〒699-2514
107-1 Fukumitsu, Yunotsu-cho, Oda City, Shimane
TEL 0855-65-2998(NPO Iwami Monozukuri Kobo)*As this is a guided tour, advance reservation is required.

Yes

Yes

One of the most unique forms in the world."1/P

Arareishi Production
area of Matsushiro Mine

The aragonite from the Matsushiro Mine, which occurs as sphericalclusters of translucent crystals, sometimes as large as a volleyball, is
unique in its shape and size, the likes of which cannot be foundanywhere else in the world. Aragonite is a mineral composed of calcium
carbonate, and its composition is the same as limestone (calcite), whichis the primary raw material of cement.
The Matsushiro Mine, which produced aragonite, was also a miningsite for gypsum from the Meiji era to the 1960s. Shimane Prefecture
once boasted Japan's largest production volume of gypsum, with minesin Oda City and Izumo City supporting production, and Matsushiro
Mine being one of the main mines. Aragonite occurs near gypsum
deposits and was prized as an ornamental object due to its uniqueshape. The site is now designated as a national natural monument
under the name of “Arareishi Production area of Matsushiro Mine,” butthe mine shafts have been closed and are currently inaccessible.

Matsushiro Mine Site
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A giant rock associated with the legend of an ogre."1/P

Oniiwa Rock of Onimura

Fossilized trees."1/P

YesThis huge rock that rises over the roadside spreads out at the top like an umbrella and has a row of five holes
on its side that look like they have been scooped out. According to legend, the holes are the marks of an ogre’s
fingers, and thus the name of the rock is Oniiwa (Ogre Rock). As the rock is composed of tuff formed bysubmarine volcanic eruptions, the action of the salts contained in it has accelerated the weathering, forming its
peculiar shape and the holes in its side. This kind of weathering can often be seen on the coast, but it is rare tosee such a clear example like Oniiwa in a place so far from the sea, and it is believed that the rock contains a
lot of salts that make it easy to dissolve. Nearby are the remains of the Onimura Mine, which once produced
gypsum. It was mined from deposits formed in connection with the volcanic activity that created this rock.

Stratified sea cliff."1/PThe Silicified Wood of Hanenishi

The Silicified Wood of Hanenishi, a national natural monument, is a large fossil tree that stands out for its
peculiar appearance. It juts out diagonally from the coastal cliff face and one end continues to the bedrock on theseabed. This fossil, presumed to be a tree of the fagaceous family, was buried by a volcanic eruption just a little lessthan 15 million years ago. The silicified tree was swept away by the wave of debris that accompanied the eruption
and was buried near the coast at the time. It is known that there are many silicified trees lying on the seabedaround the Silicified Wood of Hanenishi, and you can imagine how the wave of debris would have knocked down
and carried away the trees of the forest. It is said that when the nearby Kute fishing port was built in the earlyShowa era, many silicified trees were pulled up from the seabed. One such fossil, a particularly large specimen, isplaced in the schoolyard of Kute Elementary School.

Cave shrine

Tategamiiwa Rock."1/P

The cliff along the coast reaches a height of 80 meters. The clear
strata and the island rock that looks like it has been cut off fromthe cliff are impressive sights. It can be seen clearly from the train
windows on the San-in Main Line, and is a prominent landmark of
the eastern part of Oda City. The light-colored layers are tuff, madeup of volcanic ash and pumice, and the darker layers are composedof conglomerate. These layers were formed on the coast about 15
million years ago. The strata indicate that there were repeated
volcanic eruptions nearby.
Up until 1950, there was a lake called Lake Hane to the west of therock. The lake was used as a port until the middle ages, and theruins of an ancient temple on the shore tell the story of ancient
trade activity. In other regions, there are many similar examples ofsuch rocks called “ Tategamiiwa” that ser ve as
landmarks for harbors and for praying for a safe
voyage. This Tategamiiwa Rock has likely also served
as a landmark for the port.

Shizunoiwaya Cave

Shizunoiwaya, written of by Oishi-no-Suguri-no-Mahito
in the ancient Manyoshu anthology, is the legendary place
where the deities Onamuchi-no-Mikoto and
Sukunahikona-no-Mikoto lived for a time when creating
the land, and Shizunoiwaya Cave is said to be thelocation of that place. The cave has two mouths and is 45
meters deep and 13 meters high. Long ago, it was a placeof worship, and Shizuma Shrine used to be enshrined
within the cave. A torii gate still stands at one mouth ofthe cave. The bedrock of the cave was formed by thedeposition of volcanic ejecta about 15 million years ago,
and the faults and dikes are intricately intermeshed,
revealing the intensity of the crustal movements thatformed the Japanese archipelago. The wide space within
the cave was formed when waves eroded the fragile partsof the rock cracked by the faults.

15-million-year-old tree."1/PThe Silicified Wood of Nima

On the wave-cut platform of the Nima coast, where you can see the vivid green tuff, two large tree fossils(silicified wood) lie exposed. They have been designated as natural monuments of the prefecture under thename “The Silicified Wood of Nima.” If you look closely at the silicified wood lying on the wave-cut
platform, you will notice veins of small, tightly packed quartz crystals running through the cracks. Quartz
is a mineral made up of silicon dioxide, and this component is what turned the trees into stone. More than 15 million years ago, the trees were buried in
volcanic ash. Hot spring water then seeped into the wood and silicon dioxide that had been dissolved in the water solidified inside the trees, turningthem into hard rocks. Although they retain the appearance of trees, their components have been almost entirely replaced, and they are now masses ofsilicon dioxide minerals such as quartz and agate.

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A rocky mountain towering over the road."1/P

Mt. Ryugan (Tatsuiwa Rock)Mt. Ryugan is a peculiar rock with huge, ragged peaks that reach up to the sky and overlap like waves.
Located at the summit are the ruins of Iwami Castle, one of the mountain castles that guarded the Iwami
Ginzan Silver Mine. This rock is the part of a volcanic conduit where magma split the ground and roseup when the volcano erupted about 15 million years ago. When the magma stretched out and hardenedin the direction it was rising, streaks called “flows” were formed, and as weathering progressed along
these streaks, these shapes that stretch up toward the sky were created. The rock has several holes
formed by weathering, the insides of which are a reddish color, likely due to deposits ofiron oxide sediment, which makes them look like dragons' mouths. The largest
rock wall is covered with trumpet vine, which is one of the city's naturalmonuments, and you can see vermilion flowers in the summer andvivid red leaves in late autumn.

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