The Sharpening Stone Bearing Mountains of Kyoto, Japan
The Ultra Tamba Terrane, a shallow sedimentary layer of rock in the mountainous central region on the island of
Honshu lays in a SW/NE direction. Within this terrane are the origins of stone suitable for the purpose of polishing
swords first discovered in 1190 at the dawn of the Kamakura Period and exploited without interruption until the
middle of the 20th century by individual mining firms.
Although there may be some exceptions, you will find that in modern times and olden days that most all of this
mountainous land near Kyoto containing this ancient layer of stone was and still is owned by the various sects of the
Buddhist and Shinto religions. Over the centuries these sects have chosen to lease out the mineral rights to miners
instead of working the land themselves and all this was conducted essentially on a verbal agreement and for what
amounts to a small fee. There are scant written recordings of the continuous development regarding the mining
rights by the succeeding generations of specific families these many hundreds of years but there has always been
great pride in the traditions and oral histories that have passed on down amongst the miners. It has always been
dirty and dangerous work with few rewards beyond the lifestyle it provided for the mine owners and the local village
workers included children and women who traditionally carried much of the heavy removal burden of the stone down
the mountain sides.
The first recorded discovery in 1190 also lacks some details and largely concerns the presentation of some quantity
stone to the Regent in Kyoto for his inspection and approval which resulted in a title created “keeper of the mine” for
the finder Honma Tou-zaemon Toki-nari along with the exclusive rights to mine the stone on the spot of discovery. In
1230 the first recorded grant was issued for the sole purpose of mining this stone for sword polishing, and for the
next 500 years or so all of the best stone extracted was reserved for this end use.
This first awase-do discovery happened near the steep rural mountain village of Umegahata along what is now along
highway 162 near within an area locally called Yamashiro (Yama=mountain, shiro=castle) on Shobudani mountain
which is a minor peak but actually more like a steep hill. Some of the later Yamashiro outcroppings exploited during
the next several centuries would appear to us on a modern map to be within the city limits of Kyoto. As time went on
other mines would be developed to the east and west of Kyoto and scattered here and there throughout Japan as
the Tamba is just a part of a much larger geological terrane that reaches into eastern Japan and into a small area of
The main extraction however for the finest finishing stones resided in this general location and emanates out from
the western edge of the city limits of Kyoto and extends for about 25 miles to the west and out beyond the town of
Kameoka. Using of Mt. Atago as a center landmark you will find in the stone trades are the terms; higashi-mono or
east of Atago mountain mines, and nishi-mono or west of Atago peak mountain mines. Mono actually translates as
“things” but among stone people they are all thinking about source mines.
The original use of the term Hon Yama as I said before spoke of the area where the first stones were found by
Honma-san, but a sort of dual meaning has evolved in more modern times to include and describe the mines which
were all right in or near Umegahata on Shobudani mountain as Hon Yama mines or Hon Yama stones. The term Hon
Yama would later in the 20th century be further adulterated to include many other mine locations and or even to mean
“in the spirit of” the original location.
I conjecture that the first stone was simply found on the surface of the ground as loose rock by Honma-san, likely at
the higher elevations or even at the very crown of a mountain itself where the stone lays bare to erosion. Whether the
finder picked it up while searching for such a rock with sharpening abilities or just happened to figure it might be
useful is unknown, but it is certain that at that time in Japan the sword culture was in full bloom and sharpening
stones were in demand.
Nakayama (naka=middle or middle yama=mountain) being the center point in the of that ancient area, was located
generally in the middle in relation to the city of Kyoto and the further away peak of Mt. Atago.
The higashi-yama mines are the oldest of the famous mines and the first stones found were within walking distance
of Kyoto. These early caches of awase-do were logically reserved for polishing swords but eventually things
loosened up during the late Muromachi and early Edo periods. At that time all of the stones from the Hon-yama were
controlled by the Honami clan, a very powerful clan who also acted as the officials in charge of grading the swords of
the Shogun. The Honami clan opened up and developed mines outside of the Yamashiro, and in the middle Edo
period began free up and allowed some stones to be used for sharpening chisels, plane blades and razors by
With the emerging influence of the powerful Edo Period merchant class, more and more quality stone was allowed to
filter out into the various trades. Because of this new found market for quality finishing stones, mining increased,
while at the same time the actual battle use of swords decreased. The Edo Period was a time of peace and
prosperity, the building trades with their localized guilds were busier than ever with the mining industries following all
trends hand in hand. The mining regions were expanded and some mining techniques were improved but mostly the
workers just got busier and worked harder and with more employees.
The crush and demand for abrasive materials to fulfill the needs of the Japanese armies and industries during the
three big early wars, the Sino-Japanes War , Invasion of Taiwan of 1895, the Russo-Japan War 1904-05 and two
World Wars that followed quickly depleted what would have in peaceful times and normal demands taken hundreds
of years into our future to do so. The finest and oldest mines closed down one by one, and as they did the city of
Kyoto spread a little further into the mountains. The traditional higashi-mono mines of Umegahata are closed, only a
few newer wishful thinking shafts are being picked here and there. The great stone has been removed and all the
mountains have been walked by miners looking for new deposits. In the nishi-yama mountains to the west of Mt.
Atago some mines are still in limited operation. All of them are scaled back with either family members working the
digs and cutting shop, or like the Ohira mine, that two generations ago had 20 full time employees and now only has
one part time worker.
The coupe de grace for the traditional mines was the advancement of quality synthetic stones for the various trades,
and the prevalent use of power tools in the building trades. Natural awasedo sharpening stones are still favored by
many of the traditional crafts people who's time tends to be secondary to the quality of their work. Tea house
carpenters, furniture makers, knife makers, and sword smiths all relay on a particular attention to the finish on their
tool edges and the resulting sheen they leave on their finished products which they perceive can only come from
using natural stones. The Japanese governments office on culture for instance is keen on the inventory of uchigumori
stone, the only abrasive product in the whole world known to create the various traditional surfaces finishes on
historic Japanese swords. The Ohira mine is the last source of true old style quality uchigumori.
In closing it should be noted that although no new mines have been opened recently, and no new veins of high quality
awasedo stones have been found, the ecological demands and limits involved in opening a new mine are a factor to
deal with. The traditional mines were dug into the steep hill sides with small entrances and the tailings or waste
stone was simply dumped over the side near the mouth of the tunnel. Modern environmental rules prevent the
building of roads on these fragile and very steep hill sides, the potential water run off into local streams is an issue
associated with the general erosion and waste disposal. Traditionally harvested stone was moved down into the
valley on the backs of workers, or sleds on skids were used, then in the 20th century high tension cables were strung
for zipping small quantities at a time. These are all very slow and costly ways of moving a heavy product from point A
to B. Labor laws no longer allow children to work in the mines as the once did, and wages in Japan's busy industries
are too high for this type of low volume work. And finally the makeup of the stone found in these mountains is not
granite, nor is it any other structurally sound stone, all the digging is through sedimentary stone and this stone does
not favor safe digging conditions. Tunnel cave-ins are an issue, the use of dynamite is not favored because it causes
micro fractures in the awasado. So it all boils down to lots and lots of heavy manual labor in dangerous and dirty
conditions, not a likely job description for a young adult to be attracted to as a career.