Japanese Whetstone Glossary

Japanese Whetstone Glossary

Japanese Whetstone Glossary

Tennen Toishi Glossary copy.jpg


Ai-ishi Naori – ????

Translation: ‘Meeting Stone Strata’ – the literal
translation is ‘Synthesis Becomes Stone’. One of the 3 strata that Japanese
natural whetstones originate from. Stones from this strata are known to be coarser
and softer than those from the Honkuchi or Chuishi Naori. Hideriyama stones come from this strata.

Aisa – ??

Translation: Meeting. This is a layer of stone in the Honkuchi
Naori, it is located below Tomae and above Namito.

Amakusa – ??

These whetstones are quarried in Amakusa, Kyushu. There are
two types: red and white. The white examples are usually finer and slower, the
red variety are very coarse (800x-ish) and faster. The grain structure is often
uneven and difficult to work with when honing razors.

Aoto – ??

Translation: Blue Whetstone. Ao = blue, To = whetstone. This is a
lower to mid-grit type of whetstone. Most known to have been mined in the Tamba
region. Aoto can be soft, or somewhat harder. Many of them are soft and coarse,
but the harder examples are known to be much finer. In the past, an Aoto’s
qualities were assumed to be one way or another based on exactly where it was
quarried. Tamba is a word used to generalize the area where Aoto was mined, but
there are precise quarry locations that are now almost forgotten, such as Sakei,
Kouzaki, etc.

Aratoishi – ???

Translation: Rough Grindstone. Arato (??)
stones are used at the beginning of the heavy work when shaping a blade. These coarse grained stones are used for
cutting steel and establishing geometry. A sword polisher will have Arato
stones of several types of varying grit; these stones are somewhat coarser than

Asagi – ?? or???

Translation: Light Yellow. This is a color that is
confusingly attributed to blue, grey and/or green whetstones.

Atagoyama – ???

A mine at Atago Mountain,
it’s known to produce large clean whetstones from the Chu-ishi naori. These
stones often have this stamp;
??????. Atago-Kouzan-Awasedo.

Atarazuno hari

Reflective needle, point or dot pattern. This ‘safe’ pattern
is said to be a very uncommon characteristic. See Harike for the toxic variety.

Atsu – ??

A coarse Mikawa Nagura, usually used for sharpening scissors
and similar cutting tools.

Awasedo – ??

Translation: Finishing stone.



Ban – ??

A type of Mikawa Nagura, one of the usable layers of stone
that are quarried, generally used for sharpening edged tools.

Bestu Dai Jou – ???

Translation: Superior Selected Grade. One of the Asano
quality stamps used on Mikawa Nagura; it indicates that the stone is white with
a uniform square shape.

Betsu Jou – ??

Translation: Superior grade. One of the Asano quality stamps
used on Mikawa Nagura; it indicates that the stone is white with an odd shape.

Binsui – ??

This is the first stone that follows Arato or Kongo-Do in a
sword polishing progression. These are Nakato, or middle-ground whetstones that
are quarried at Amakusa on Kyushu.
The Binsui-Do is used to remove the scratches from Kongo-Do.
An approximate grit range for these stones might be rated as being around

Botan – ?????

Peony. The coarsest Nagura in the
typical 3-stone Nagura set used by people honing razors.



Chu Nagura – ???

This is a
mid-range stone; It does not come from Mikawa. In a sword sharpening
progression, it is the last stone before Koma Nagura Do. High quality Chu
Nagura can be used successfully when honing razors or sharpening cutlery.

Chu-ishi Naori – ?? ??

Stones from this Naori are softer and less fine than those
from Honkuchi. They are generally very consistent and of good size. Whetstones
quarried at Atagoyama are from this Naori. These stones are described as having
the ‘ball’ form, which means they are all one layer.



Diamond Nagura

Also referred to as a ‘DN’ – a small diamond plate used to
generate slurry.



Enshou – ??

Translation: Firecrackers. This characteristic is the
result of sulfur in the stone; usually seen as blue/black spots or lines. This
can also be referred to as Ao-Renge. It’s been said that the sulfur in the
stone can cause a discoloration in certain types of steel.



Gotogi – ??

Translation: ‘Layered, or to be together’ – many Japanese Natural Whetstones, such as
those from Tomae strata, were formed with layers that can be seen on the sides
of the stone.

Goma – ??

Translation: ‘Sesame Seeds’ – These are small black dots
that look like sesame seeds. Many people believe this pattern indicates that the
stone will have good speed. Goma can be ‘safe’ or ‘toxic’; if they are too
hard, they can scratch a fine edge.



Ha – ?

This is the hardened steel section of a blade that forms the
cutting edge.

Habutae – ???

Translation: Fine Silk. A color characteristic attributed to
certain very white Suita, sometimes also called ‘rice cake’.

Hagane – ?

Translation: Steel. Also called kotetsu. Literally, this is
the harder ‘edge’ steel that is supported by an outer layer of soft Jigane.

Hamon – ??

Translation: Blade Pattern.
On a sword, this is the outline of the hardened zone known as the
Yakiba, which terminates at the cutting edge or Ha.

Hakka – ??

This was a whetstone mine that produced many good stones.
Generally speaking, they are usually softer and coarser.


This term is used to describe what can be described as a toxic needle
pattern. This is a toxic inclusion and it can scratch the steel and possibly
damage an edge.


This is a family name that belongs to the final owners of
the Nakayama mine. They are still in business selling Tennen Toishi.

Hazuya – ??

This is a very thin slice of Uchigumori stone that is fixed
to paper.

Hideriyama – ???

A whetstone mine known for producing good quality stones
that are generally expected to be softer and more coarse that hones from the
eastern mines.

Higashi Mono

Eastern mines
of Kyoto, e.g. – Narutaki Mukoda, Nakayama, Okudo, Ozuku and Shobudani.

Hikikoro – ? ?

Translation (slang):

Hiki – Pulling the saw/taking out from
the mine.

Koro – roller, pully – shaped like a
ball, (obscure Kun-Yomi term).

The term “Hikikoro” is a
slang term used by the miners; it refers to Koma from Koma shaved by
hatchet. The weight is about 200g.

According to Mr. Kosuke Iwasaki, Koma was
not cut with a hand saw, it was shaved with a hatchet at the mine area; the
other Nagura were cut with a saw after it was taken to the village near the
Also – see – Kiridashi

Hin Shitsu Yuu Ryou – ?? ??

Translation: Excellent Quality Product. This stamp is
sometimes seen on finishing stones.

Hon-kuchi Naori – ????

Translation: “Main Opening Strata”, the literal
translation is ‘Becomes the Mouth’. This is one of the three stone formations
that Japanese whetstones originate from. The stratum in this formation are
known for producing the hardest and finest stone.

Honyama – ??

Translation: True Mountain. These Kanji are also used for ‘Honzan’.
Originally, Honzan and Honyama were terms used specifically and only when
referring to a natural whetstone from Nakayama or Shobudani. In more modern
times, they are used generically to mean any natural whetstone.




These coarse whetstones are Nakatoish,
or Chu-Shiage stones. Reportedly, the blue-ish examples are finer than the
white ones. There has been some speculation as to the origin of these stones;
both Nigata and Kyushu have been referenced as the source.


Translation: Potato Stone. This term
refers to Japanese natural whetstones that are homogenous, without any
layering. These Toishi can be used on any side; many Aoto are potato stones.

Iromono – ??

Translation: Colorful Laundry. This characteristic shows as
abstract splashes of color; red, pink, violet and possibly other colors mixed
in as well. This is seen most often in softer Kiita stones.



Ji – ?

This refers to the section of the blade between the Hamon
and the Shinogi.

Jigane – ??

This is the softer outer layer of steel that supports the
harder Hagane.

Jinzou Toishi – ????

Translation: Synthetic whetstone.

Jizuya – ??

This is a type of final polishing stone; usually quarried at
Narutaki. It is used to polish the ji.



Kaeri – ???

Translation: Burr. A small ‘curl’ of steel coming off the apex of the cutting edge.

Kaiji Oshi – ???

Translation: Rough Polishing. This is the final stage of the
smiths work. At this juncture, the blades’ lines and basic geometry are
established. This allows the smith to inspect the steel to ensure the absence
of cracks or defective welds. Also
called Kajitogi. The smith will also add his signature, drill the hole for the
Mekugi, and add any decorative work if needed. After this, the blade will go to
the polisher.

Kaisei – ??

This is the 3rd stone in a modern sword polishing
progression. Known as Kaisei-Do, this stone removes the scratches left by
Binsui-do and it precedes the finer Chu-Nagura-Do. The approximate grit rating
for these stones is in the area of 400-600x.

Kamisori – ??

Translation: Razor. Usually indicates a Japanese-style
straight razor that does not fold into scales.

Kamisorido – ? ? ?

Translation: Razor Sword Whetstone. This quality stamp can
be found on stones that are hard/fine and selected for honing razors, or stones
that are cut smaller for use as razor hones.

Kan – ??

Translation: Ring Winding. A pattern in the stone that
resembles the age rings in a tree. Sometimes, very pronounced Kan rings can be
invasive and scratchy. The darker rings can be of a different density that
imparts a change in the feedback on the stone. However, most of the time, Kan
is not invasive and safe to hone on.

Kanato-ishi – ???

A flat metal plate for sharpening woodworking tools; a small
amount of abrasive emery powder was sprinkled on the plate.


This s a hairline inclusion that is toxic. It can be
felt under the blade when honing; it contains very hard particles that can
damage the edge.

Karasu – ??? or ?

Translation: Crow. This is an abstract pattern that
resembles a blurred flock of crows flying against the sky. It’s been claimed
that very dark Karasu spots can be scratchy, and stones with a very light
Karasu pattern are highly sought after. This pattern is associated with stones
from deeper layers, such as Aisa.

Kawato – ??

Leather strop used for final finishing a sharpened edge.


These are hairline inclusions that are safe to hone on.
They contain soft particles that will not damage the edge. They can take on
water though, and over time they can cause the stone to split along the line.

Kiita – ??

Translation: Yellow Plate. – a stone showing a pronounced yellow
coloration is called “Kiita. They
are highly sought after, and are generally seen being a bit softer than most
Asagi stones, but some Kiita are exceptionally hard.


Translation (slang):

This term refers to the leftover pieces
of Koma that are smaller than “Hikikoro”; their weight is usually
around 80-100 g.

Kizuyama – ???

One of the eastern whetstone mines in Kyoto.

Koma – ??

Translation: ‘Fine’ – Koma Nagura is the finest and usually
the most expensive of the Mikawa Shiro Nagura. In a sword polishing progression,
Koma follows Chu, and it is the last step before the final polishing steps.

Kongo Do – ????

Translation: Emery Whetstone. This is most often the 1st
and coarsest stone used in sword polishing. An approximate grit rating could be
80-220x. This is primarily used for the rough shaping of a sword’s geometry, or
heavy repair work.

Koppa – ??

Translation: Small End. – this term is used to describe a
larger or small stone with an irregular shape. It is often used to describe a small razor
size stone also. Koppa are usually less expensive options than their
bench-stone sized brethren.

Koukyuu – ??

Translation – High class or high grade.

Kouzaki – ??

This was a mine in the Tamba area where
Aoto were quarried; the stones from this location were generally harder and
finer than stones from the other mines.

Kyoto – ???

Translation: Kyoto-Fu. Kyoto is a prefecture in Japan that is
located in the Kansai region on the island of Honshu. The capital city is also
named Kyoto. The prefecture of Kyoto is where many of the most famous whetstone
mines were located.

Kyoumen-Shiage – ?????

Translation: Mirror Finish.
This is a self explanatory term used to describe a very high polish on
the bevel.

Kyou-To Toku-San – ????

Translation: Special Product of Kyoto – a stamp seen on the
tops of Tennen Toishi.

Kyushu – ??

A Japanese region/island; Amakusa & Binsui Toishi, and Tsushima
Black Nagura are quarried here.




?? –
Maruichi jirushi, Maruichi brand.

?? –
Tokusen, especially selected.

It has been said that this stamp was used by Kato-san when he ran the quarry at Nakayama. Allegedly, not all stones with this stamp are from Nakayama. For whatever reason – there doesn’t seem to be any hard data on this stamp’s origin, use, or history.

Maruka – ????

Translation: Maruka Shou-Honyama. A stamp that is found on
the ends of stones quarried at Nakayama. This was used by Hatanaka, the circled
‘Ka’ character paid homage to Kato-san, the previous owner of the mine. The
translation of ‘maru’ is circle; the circled Ka translates to Maru-Ka or
Maruka. the rest of the characters are Shou-hon-yama which mean ‘Real Original

Maruoyama – ???

A western mine in
Oouchi district; known for stones quarried from
the Hon-Kuchi and Ai-ish Naori. They have 3 quarries at Maruozan (???) mountain.

Mejiro – ???

White Nagura or ‘White Eye’. This is a mid-range Mikawa Shiro Nagura.

Mizu – ?

Translation: Water. This is a color
characteristic attributed to grey/blue Asagi stones.

Mizukihara – ???

A western Kyoto mine, located in the same mountain as Ohira.

Mokume – ??

Translation: Wood Grain. A pattern that resembles the grain
found in wood.

Momiji – ??

Translation: Autumn Leaves. Often said to be specifically ‘maple leaves’. This is a pattern that
looks like leaves in/on the stone. Many say it is specific to Suita stones, but
I have seen it used to describe a leaf pattern on Tomae stones also.

Mikawa Shiro Nagura

These Nagura are quarried in the Aichi prefecture at the Mikawa Nagura Mine – ????.
When honing razors, these stones are used to create an abrasive mud or slurry on a harder finishing stone. Mikawa
Nagura can also be found cut as full sized bench stones, these are used for
polishing swords, and sharpening many types of edged tools, including

There are 12 layers of stone at the mine, but only 8 can be
used for sharpening. Botan, Tenjyou 1, Tenjyou 2, Mejiro, Koma, Atsu, Ban, Yae
Botan. For honing razors, the most commonly used are; Botan, Tenjyou and
Mejiro. Koma is also used for razors but less frequently; it is very rare and
expensive. Historically, the finest quality stone from Mikawa carry the Asano
quality stamps.



Nagura – ??

Translation: Correcting Stone. This can mean any stone that
is rubbed on top of another stone to create slurry or to smooth out one or both
See Tomo Nagura, Chu Nagura, Mikawa Nagura and Diamond

Nakatogi – ???

Translation: Medium Polish. This term
seems to be used mostly in the carpentry trade. It refers to the middle stages
of sharpening, up to and including the pre-finish sharpening.

Nakatoishi – ???

Translation: Medium Grain Whetstone. These stones are used
for the mid-range sharpening/polishing work, which is relative to the type of
edge being developed. When sharpening swords and other heavier cutting tools,
Kasei, Binsui, Chu Nagura Do, Uchiguimori and Koma Nagura Do are commonly used
as Nakatoishi.

– ??

This is a deep
strata in the Hon-Kuchi naori; it is located below Aisa and above Hon-Suita. These
stones are often hard, fine grained and very consistent.

Nakayama – ??

This is arguably the most famous eastern whetstone mine. It
was located at Atago Mountain.

Namazu – ??? or ?

This is a pattern seen in Japanese natural whetstones. It is
usually comprised of irregular lighter-colored blotches, streaks or spots on
the surface.

Naori – ??

Translation: Strata. See Hon-kuchi, Chu-ishi, and Ai-ishi

Narutaki – ??

This can refer to the mine, or the region where the Higashi
Mono or Eastern Mines are located.

Nashiji – ?? or ???

Translation: Pear-like. This is a ‘pear-skin’ pattern found
mostly on Kiita stones from the Tomae strata. Many believe that Nashiji indicates superior
cutting speed but whetstone authorities claim it is only a visual aesthetic.

Nihon Kamisori You – ?????

Translation: For Use with Japanese Razors – a stamp seen on the
top of finishing stones.


Western mines of
Kyoto, e.g. – Ohira, Mizukihara, Shinden, Okudomon.



Ohira – ??

An active western
Kyoto whetstone mine, well known for Awase, Suita and Uchiguimori.

Okudo – ??

This is a semi-active eastern (Higashi Mono) Kyoto
whetstone mine that is best known for the most highly coveted Suita in Japan.

Okunomon – ???

This western Kyoto mine was located next to Ohira.

Omote – ?

The signature side of the sword’s
nakago, it is the obvious side of the blade that faces away.

Oomura ??

A whetstone mine on Kyushu, this location was known for
producing sandstone Aratoishi.

Otoyama – ???

This whetstone mine is known for producing Suita.

Ozuku – ??

This was one of
the famous eastern mines in Kyoto.

Ozaki – ??

A whetstone mine in Kyoto.



Renge – ??

Translation: Lotus
Blossom. This coloring/patterning is specific to Suita stones. Usually seen as
a red, pink, brown or black pattern of fine lines. This visual aesthetic has no
positive affect on sharpening capabilities; some say that the presence of Renge
indicates a reduction in cutting strength.



Saeki – ??

This location is known mostly for the production of soft
coarse stones. Some examples are harder and highly sought after.

Sai Jou Kyuu – ???

Translation: Highest-grade. This stamp can be found on
finishing stones.

Shiage – ???

Translation: Finish. These are the final stages of sword

Shiage Toishi – ?????

Translation: Finishing Stone. These stones are usually
fairly hard and fine – they are the last stones in the progression and used for
the final polishing stage.

Shinden – ??

A Western Kyoto mine known for producing highly prized Suita.

Shinogi – ?

This is the ridgeline on the blade where the Mune meets the
beveled Ha.


This whetstone mine is connected to Ozuku.

Shitaji – ??

Translation: Ground Material. These are the lower stages of
sword polishing.

Shou Hon Yama – ???

Translation: Real Original Mountain. This stamp can be found
on finishing stones. Also reads as Shou
– Hon – Zan.

Shouhonyama Honkakuhin – ???? ??

Original Mountain Original Source.

this should infer that the stone comes from the area around Kyoto where the
original Honyama were mined.

Stratum – ?

A layer of
whetstone; Tomae and Aisa are two strata in the Honkuchi Naori.

Su – ?

Translation: Nest. These are small holes that were left
behind by escaping gases when these stones were being formed in the earth’s
crust. They are associated with Suita stones, but they can be found in other
layers also.

Suita – ??

Translation: Nest
Plate. Suita stones come from 3 different stratum. Most, but not all, of them have ‘su’ – small
holes or pockets created by escaping gas when the stones were forming in the
earth’s crust. Under close
inspection, su can resemble a hive or a
nest. Suita without su are known as Sunashi Suita.

Sujimono – ??

Translation: Muscle
Of. This word references stones with a lot of Suji. Often, but not always, this
characteristic is an indicator that the stone is inferior.

Sunashi – ???

Translation: No
Nest. This is a type of Suita stone that has no su.

Suji – ?

Translation: Muscle. This refers to lines in the hone, some
of which may be ‘safe’ while others can be ‘toxic’ Kesuji and Kanesuji.

Sword Grade – ???

Translation: Sword with Knife. This Asano quality stamp can
be found on large pieces of Mikawa Shiro Nagura; it infers that the stone is
high quality and good for use when polishing swords.




Translation: Egg. Used to describe the color of stones with a specific type of mottled creamy yellow coloring.

Takao – ??

This whetstone mine in Kyoto was well known for producing

Tajima-To – ???

Translation: Medium grit whetstone.

Takashima – ??

This whetstone mine is located northeast of Kyoto. Stones
from this location come from the Hon-Kuchi Naori, and they are generally very
consistent and fine but a bit soft.

Tamahagane – ??

Translation: Jade Steel. A type of steel used by master
sword smiths in Japan.

Tamba – ???

Translation: Tamba no kuni. This was an old province in
Japan, this area is where many Aoto Toishi were quarried.

Tengu-do – ???

Translation: Tengu whetstone. This is a coarse stone with red
stripes. It is similar to, but more aggressive than, Amakusa.

Tenjyou – ??

Translation: Heaven
or Sky. A mid-range Mikawa Nagura, also spelled Tenjyou.

Tenjyou Suita – ????

A shallow strata or layer in the Hon-Kuchi Naori.

Tenjyou Tomae

A stone strata located in the Ai-Ishi Naori.

Tennen Toishi – ????

Translation: Natural whetstone.

To – ?

Translation: Whetstone or

Togidoro – ??

Stone slurry mixed with steel, aka – swarf .

Tomae – ??

This is the largest strata in the Hon-Kuchi Naori; there are
48 veins of Tomae. It is found above the
4 layers of Aisa, and below the 2 layers of Senmai strata.

Toishi – ??

Translation: Whetstone.

Tojiru -???

Translation: Close. This term refers to the lubricating
abrasive paste, or slurry, made with Uchiguimori. It is often loosely
translated to mean ‘juice’, when referring to any slurry on any Tennen Toishi.

Tokkyuu – ??

Translation: High grade. One of the Asano quality stamps
used on Mikawa Nagura; it indicates that the stone is striped with an odd

Tokkyujou – ???

Translation: Superior High Grade. One of the Asano quality
stamps used on Mikawa Nagura; it indicates that the stone is striped with a
square shape.

Tomo Nagura – ??? or ?????

Translation: Total Nagura. This term refers to a small piece
of stone used to raise abrasive slurry on the Honzan.

Tomoto Kyho Togi – ??

Translation: Co-Abrasive. Also translates to – Paired Hone.

Torato – ??

Translation: Tiger Whetstone. This term is often used when
referring to Amakusa Toishi that have reddish ‘tiger’ stripes.

Tsushima Black Nagura

A whetstone quarried on the island of Tsushima, off the west
coast of Nagasaki. It is a mid-range whetstone that produces slurry that breaks
down to a very fine degree.

There are two types of Tsushima Black; Ocean and Mountain; the Ocean Tsushima
Black is quarried underwater.



Ukeai Junshou Honyama –

Translation: Guaranteed Real Nakayama. This stamp can be
found on the top of whetstones.

Uchiguimori – ?? or ????

A specific type of Suita that is traditionally mined at
Ohira. There are two types, Hato and Jito; they are used for bringing up the
polish to accentuate the Hamon on a sword or the steel’s patterning on a knife.
Often used as Hazuya.

Uchigumori Hato – ????

This softer Uchiguimori is used to bring out details in the

Uchigumori Jito – ????

This harder Uchiguimori is used to bring out details in the Ji.

Umaji – ???

This Nishi-mono whetstone mine was
located on the west side of Mt. Atago along with Oohira and Shinden. Generally,
but not always – this location was known to produce softer stones from shallow

Umegehata – ???

A valley area in Kyoto Japan, Nakayama and other famous
mines were located here.

Ura – ?

secret side of the sword that faces inward, toward the body



Wakasa – ??

This is a whetstone mine at Miyama Mountain. Some Wakasa are
very hard and fine, but many are a little bit soft.



Yaginoshima – ???
or ????

This whetstone mine is located east of Ohira and known for
producing good Suita.

Yake – ?? or ??

Translation: Burnt. This is a dark orange/deep umber
coloring most often seen on Suita stone. When and area of stone shows very dense
and hard Yake, it can be problematic to hone on and it can scratch the blade. This
word is also used to refer to any pronounced splashes of color on a stone.

Yakiba – ???

Translation: Grilled Blade. This is a sword
term; it refers to the hardened, tempered area from the top of the Hamon to
the edge

Yamashiromate – ????

Translation: Yamashiro (Mountain Castle) Inscribed
Whetstone. This is a 330Mate Stamp; said
to mean that the stone comes from the Yamashiro region in central Kyoto.

Yari Kanna – ? ?

Japanese woodworking plane

Yae-Botan – ?????

A coarse Nagura quarried
at Mikawa. This layer is known to sometimes have sand layers and quartzite
inclusions. These Nagura were usually faster and coarser than Botan.

Yuuryou Shiage To – ?????

Translation: Superior Finishing Hone. This quality stamp can
be found on Awasedo.

I’ve been interested in Japanese Natural Whetstones far
longer than I’ve owned any of them. When I first started getting interested in
these stones, I was confused by many of the terms used to describe them, so I
started saving simple text files on my computer with explanations and
definitions. What follows is the result of me finding the time and energy to
compile all of those notes into one place.

This is not meant to be the end-all of information; one
thing I’ve learned is that there can be many definitions for each word or term.
Another fact is that sometimes, I make mistakes. This glossary will be a work in
progress and I will update it as I learn more.

© Keith V Johnson 2014