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Japanese Natural Stones (JNATS) Glossary & Kanji

Aiishi Nari or Ai-Ishi Naori- 合石成り

One of the three Strata groupings along with Hon-Kuchi Naori and Chu-Ishi Naori which run through the Kyoto (aka Yamashiro) that the majority of Awasedo are mined from. These stones actually have a different layering classification than the terminology usually used (those for Hon-Kuchi Naori) but typically stones are assigned those same names (such as Tomae instead of the proper Tenjo/Honto/Shiki-Tomae terminology). Hideriyama, Jissei, and Segi-Dam are some of the mines from this Strata grouping.

Aisa – 合さ

Somtimes called the Karasu layer, this is a layer comes from the the Honkuchi Naori strata and is considered the 6th usable layer located on the boundary between Tomae/Namito layers. There are only four levels of stone to this layer. It is often known to be very hard. Karasu stones almost exclusively come from this layer, though not all Aisa are Karasu. When it is not Karasu it more commonly has the Tamamoku attribute, but that is not individually unique to the Aisa layer. Aisa stones tends to have a lot of abrasive force but also a higher probability for impurities.

Aiiwatani – 相岩谷

A Higashi Mono (Eastern Mine) north of Kyoto located by Takashima and Wakasa. This area is known for its high-density stones. Aiiwatani tends to produce harder stones.

Aizu – 会津

A Northern Japan mine producing medium-coarse whetstone from Fukashima. Useful for knife sharpening with a toothy edge, late middle stage polishing and for setting bevels on straight razors. This stone is a form of Dacite with Feldspar inclusions which show up as white dots within its surface. It was quarried in Fukushima. While most mines stopped production in the 1980s, due to an incident within the mines causing wide-spread lung disease all stock is from 1950s or before.

Aka – 赤

Red. Sometimes used interchangeable with Akapin when referring to the coloring of the stone, though since Akapin is a stratum that can be confusing. When referring to the coloring of the stone, it indicates deep red and pink colors throughout the stone or of the stone entirely. Not to be confused with Iromono or Keppan.

Akapin – 赤ピン or 赤不动

Shallow layers, softer stones. Used to be very common, it is less so now. This can also indicate the coloring of the stone itself, usually a deep red to pink color. These stones can range in coarseness and fineness, it is hard to draw a specific broad performance level for them. Soft and fine ones are capable of razor work and are very nice to work on.

Amakusa – 天草

A South-west Japanese mine producing whetstones from the Kyushu area. Amakusa stones can come in different varieties, typically delineated by their coloring (white or red) with exceptional examples of the white variety sold as Binsui (all Binsui are Amakusa but not all Amakusa are Binsui). Lower quality stones that do not carry the Binsu name can have impurities and negatively impact the edge of chisels, razors, thin blades, etc. This mine is still active.

Ani Ishi – 阿仁石

A Northern mine producing rough quartz rock and crushed stone.

Aoto – 青砥

A Nakatoishi (middle grit) stone that used to be extremely popular with Japanese carpenters but has since fallen out of favor for softer synthetic stones. Typically divided into two categories, soft and hard Aotos. The soft variety are often identified by the dots within its surface being brown (or having brown streaks in the stone) while the harder variety often has black spots instead. This is not a definitive rule though. Softer stones mud extremely quickly and are very aggressive, analogous to a 1k stone while the harder variety can range drastically in density/hardness and go up to around the 3k area. Aotos were mined in the Tamba/Tanba area with many different mines producing stone. Kouzaki often produced more homogenous and finer versions of these which were (and still are) more sought after than other varieties.

Arato or Aratoishi – 荒砥石 or 荒砥 or 粗砥

Ara-toishi are the first and most coarse type of stone typically used on a blade to start the polishing, grinding, or sharpening process. They are typically made of sedimentary sandstone from top strata layers. These stones are often analogous to x150-x800 synthetic grit and have become greatly replaced by the coarser synthetic whetstones which offer faster performance with less rogue or inclusions within the stone.

Asagi – 浅葱 or 浅葱色 or 浅黄

This color indicates a very light/thin colored indigo, almost neutral grey. It can also mean yellow or light yellow. There are sources that claim it to be a derivative of the Japanese word for indigo or light blue, while others say it stems from the Japanese words for setting sun or mist. Generally, this is a color that is attributed to grey whetstones. It should now be accepted that it could range from blue to even dark yellow as that is how the term will be commonly used.

Asano / Inspected by Asano – 検浅野

Red stamp originally used by Nagayuki Asano to grade nagura based on strata and progression performance. The stamp was passed onto Sakamoto Misao for the same purpose and continues to be used on Mikawa Asano Nagura to this day which have been properly inspected.

Atagoyama – 愛宕山

This mine is known for producing large blocks of very easy to work with softer Awasedo stones with a bit coarser grit than others. Though considered a Western Mine (Nishi Mono) unlike other stones from that area of Kyoto it originates from the Chu-Ishi Naori strata group. This results in the grit of the stone being formed differently (golf ball rather than flakes) and as such is responsible for its soft and fast performance.

Atarazuno Hari – 当たらない針

A term which means Needles Without Hitting in Japanese. The presence of thin “needle-like” black lines or dots which are sometimes but not always reflective. It is a fairly rare visual quality and the safe version of Harike.

Atsu – アツ  

Thick. A medium-coarse Mikawa Nagura which comes after Ban and before Yae Botan. This is a good all-around nagura for tools, knives, and the very start to razor progressions. Some Atsu are known to have sand inclusions, so pockets within the stone should be carefully checked.

Awasedo –  合砥

Often mis-translated as “Go-To” this moniker is used to refer to a stone which is finer than Shiage Toishi, and the final finishing stage in the stone progression process. This is the more common term used to refer to all finishing stones and often times the Shiage Toishi step is colloquially combined into the Awasedo naming convention as one larger step.

Ban – バン  

No distinct translation. Often mistranslated as “Van”. This is the second coarsest layer from the Mikawa mine and unsuitable for use in any razor coarsest progression. It is more traditionally used for thick knives and tools.

Bestu Dai Jou – 別大上  

Indicates Superior Selected Grade. One of the six visual grading stamps used on Mikawa Nagura which indicates the color and shape. In this case, it is similar to a Betsu Jou stone (white) but with a square/rectangle/etc. shape (dai). Despite the name difference, these are not inherently superior to other colors or shapes of Mikawa stones – it only indicates visual and physical descriptors.

Betsu Jou – 別上

Indicates Superior grade. One of the six visual grading stamps used on Mikawa Nagura which indicates the color and shape. In this case, it is referring to a stone with a white base color but an irregular cutting. Despite the name difference, these are not inherently inferior to other colors or shapes of Mikawa stones – it only indicates visual and physical descriptors.

Binsui – 備水

An early stage Nakatoishi stone and is the high-quality version of the Amakusa stone. In a traditional sword polishing process, these are your first stone after your initial shaping of the blade on an emery stone (Kongo). Very fine versions of these stones can be used to set bevels on razors, but typically they are best relegated to early sharpening tasks or analogous 1k knife/tool work. This mine is still active.

Botan – ボタン

A team meaning peony flower in Japanese. A medium-coarse Mikawa Nagura and the coarsest Nagura in the typical 4-stone Nagura set used by people honing straight razors. There are two version of this nagura with a “Yae Botan'” variant which performs similarly but requires a bit more time to break in. These nagura can also make very good knife sharpening nagura as they retain good cutting power. This is often mistranslated as Button and shown as Button Nagura.

Ceiling Nest Plate – 天井巣板 or 天井巢板

This is combining two terms we frequently see for different stones or strata, Tenjyou (天上) and Suita (巣板) to indicate the 2nd useable layer of the Hon-Kuchi Naori strata group.

Chu Nagura – 中名倉

A nagura stone from the same area as the Mikawa nagura, it has wide range of performance and is one of the stones traditionally used in sword polishing (between Kaisei and Koma). Chu is from its own mine on Kada mountain beside the mountain Mikawa comes from, but often Mikawa Nagura are sold under the Chu name when the layer of Mikawa is unknown. They are technically different things, but the term is so often used this way it needs to be considered. Anything Mikawa Chu isn’t real Chu, but may perform similarly.

Chū To – 中砥

Medium Grit Stone. One of the Ryūdo Kubun 粒度区分 or Granularity Classification.

Chu-ishi Naori – 中石 成り

One of the three Strata groupings along with Hon-Kuchi Naori and Ai-Ishi Naori which run through the Kyoto (aka Yamashiro) that the majority of Awasedo are mined from. This layer is distinct from the other two as it has one large usable layer rather than multiple different layers. This results in many big blocks of stone coming out with the same fast cutting Awasedo functionality as is commonly seen in Atagoyama and Osuki mines.

Diamond Nagura

A diamond plate which can be used to flatten or generate slurry on a whetstone. Atoma Diamond Plates are a common high-quality brand. I believe this term was popularized by Alex Gilmore.

Enshō or Enshou – 煙硝  

A term for firecrackers in Japanese. Unlike Ao Renge or Kuro Renge (黒蓮華), this term is used to refer to black dendrite formations within the whetstone when we are referring to non-Suita stones. These formations are almost always non-toxic.

Gokudo – ごくどう

Rogue or Wicked. It is a nickname for the layers of unusable stone in Higasshimono mines which surround the usable layers. It is a very hard layer and can be very frustrating for miners to work through.

Gokujo – 極上品

A stamp on whetstones indicating a select or top-quality whetstone.

Gotogi – 層状

This refers to the visual layering seen on the side or surface of the whetstone. This visual formation is the result of where sedimentary silt piled on top of one another from ocean or geological currents and pressed them together. When the Gotogi quality is ontop of the stone it can also be referred to as Masame.

Goma – 胡麻

A term for sesame (seeds) in Japanese. When used for whetstones it indicates the presence of black dots within the stone’s formation, though these dots can take a variety of shapes from small lines, blotches, to round circles. This is typically considered a non-toxic quality in stone

Grindstone Layer / Whetstone Strata – 砥石本層部

This is the kanji for the usable section of Chu-Ishi Naori.

Habutae – 羽二重 or 百拔

This term is used to indicate an extremely white and pure Suita stone which looks to have a silken feature to it. This is a very rare and sought after visual quality in Suita stones. This also loosely refers to Rice Cake or Silk Weave.

Hachimai or Hachi-mai-sō -八枚層

This refers to the 3rd usable layer in the Hon-Kuchi Naori and translates to 8 layers. It has this name as there as eight levels that comprise the entire Hachi-Mai-So section of the Hon-Kuchi Naori. It is known for being harder and finer stone which is sought after for razor/barber hones. It can be a very difficult stone to identify as it has very few unique visual characteristics.

Hakka – 八箇 or ハッカ

A Nishi-Mono stone from the Kyoto area, it was known for being a very soft stone with a well-balanced fineness to it. Hakka stones carry a reputation for being extremely useful in all areas of use for JNATs (polishing, honing, sharpening) and as such are very sought after stones. Due to their softness, these stones should always be sealed on the sides and back to avoid cracking or disintegration.

Harike – 針

A term meaning Needle in Japanese. The toxic version of Atarazuno Hari. This is the presence of thin “needle-like” black lines or dots which are almost always reflective. It is a rarer form of toxic inclusion.

Hatahoshi – ホハシタ

Often seen on old nagura sold that were inspected by Iwasaki. A sticker is usually affixed to the stone that says Hata Hoshi with a star between two Japanese flags. These are often exceptional nagura, however it is easy to forge the sticker.

Hatanaka – 畑中

This is the family that owns the Nakayama mine and has a very unique large circular stamp on their whetstones. Stones which retain this stamp often go for considerably more than other stones and are considered to be superior quality. Recently Hatanaka has authorized the Nakayama mine to be reopened for limited use.

Hazuya – 刃艶 

A type of finger-stone used in traditional sword polishing along with Jizuya. It is used to polish the Ha or hardened steel of a sword.

Hideriyama – 日照山

A Nishi Mono stone which comes from the Ai-Insi Naori strata group. These stone are often seen as good replacements for the harder to find Hakka stones, having a similar softness to them which is balanced by a very usable fineness to their grit. Compared to Hakka stones, they lack some of the more aggressive metal removal/speed Hakka has but are still more than acceptable performance.

Higashi Mono – 東モン

Eastern Mines or East-Side Mountain, these are the mines positioned east of Mt. Atago.

For a more comprehensive list of these mines check here.

Hinshitsu Yūryō – 品質 優良

A stamp on whetstones indicating an excellent quality whetstone similar to Gokujo.

Hoboyo – 鋒錢用 or ほうぼうよう

Sometimes called “硯”, Suzuri, or Inkstone these are Mikawa nagura that are unmarked from the layer and used to flatten out the high spots or sides of your whetstone. Often a diamond plate in modern use takes this function, but these are sold specifically for this purpose. They tend to be smaller than regular Nagura, being thin and larger than most coins but smaller than your palm. These stones will still carry the Asano and Mikawa stamps but will lack a strata stamp. They will be marked “鋒鋩用” instead of the normal Betsu or Tokkyuu designations.

Hon Shiro – 本白

One of the usable layers from the Ai-Ishi Strata. This is often just sold as a “Suita” stone.

Hon Suita – 本巣板 or 本巢板

A total of 6 seams to this Suita layer. They are highly sought after and come a variety of colors and attributes. These are usually hard Suita.

Hon Tomae – 本戸前

The fourth usable layer within the Ai-Ishi Naori. Usually this is just called Tomae along with the other Tomae layers of Ai-Ishi Naori when sold.

Hon-kuchi Naori or Honguchi Naori or Honkuchi Nari – 本口成り

One of the three Strata groupings along with Chu-Ishi Naori and Ai-Ishi Naori which run through the Kyoto (aka Yamashiro) that the majority of Awasedo are mined from. This could be considered the main Geological event most of the stones are pulled from and where the vast majority of Awasedo on the market are from. Many mines are connected by this seam, which runs from Maruoyama/Ouchi/Yaginoshima east across the Tamotsu-gawa (Katsura) River, to the Hakka mine, South-East to Okunomon, Ohira, Atagoyama, Ozuku, Okudo, Nakayama, then turns north to Narutaki and Aiiwatani. Certain levels of these seam can often matchup between the mines, creating similar stones and colors such as for Aiiwatani and Nakayama.

Honyama – 本山

This stamp is used to indicate stones from the True Mountain of Mt. Atago. Originally this referred specifically to Nakayama and Shoubudani stones, but has since become analogous to all stones pulled from the Kyoto area and 3 main Strata groups. Often mistranslated to Motoyama or Honzan by automatic translators.

Ikarashi – 五十嵐

Also referred to as Igarashi, Igarashi To, or Kasabori. These medium coarse whetstones are Nakatoishi and sit in about the middle of the range of those stones. Reportedly, the blue examples are finer than the white ones. These stones are from Niigata, with a few different mine veins around the area. The original mine vein was in Kasabori, Niigata but has since been exhausted. Kasabori Ikarashi is very hard and very close to Aizu in performance, whereas newer Ikarashi which drops the Kasabori name tends to be a little softer and a little course making it more clearly slot between Binsui and Aizu in performance. Non-Kasabori Ikarashi will be much more pure emerald in color when wet, whereas Kasabori Ikarashi will have white dots like Aizu and retain the very dark Emerald color compared to the lighter emerald color of Aizu.

Iki Murasaki – いきむらさき

Purple-ish. It is an uncommon color of Maruoyama stones, commanding a higher price.

Imo-ishi – 芋石

This term “sweet potato stone” refers to homogonous stones that lack any form of the “Gotogi” layering. This is less common for Awasedo stones but is fairly common for Naktoishi stones such as Aoto, Aizu, and Ikarashi stones.

Ipponsen / Ippon Sen – 一本撰

First Class / First Selection.

Iromono – 色物

A term indicating colorful fabrics in Japanese. 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. Not to be confused with Aka where red is the only color besides the base stone coloring.

Jinzo Toishi – 人造砥石

Kanji used to indicate an artifical whetstone.

Jizuya – 地艶 

A finger stone used alongside Hazuya in traditoinal sword polishing. Jizuya is harder Kiita stones typically sourced from Nakayama or Narutaki to polish the softer steel areas of the sword.


Shortened term used to refer to Japanese Natural Stone / Japanese Natural Stones.

Kaisei – 開成

A middle stage Nakatoishi stone with an approximate grit rating would be 3k-5k. Uncommon to find now adays due to its use in traditional sword sharpening where it sits between the Binsui and Chu Nagura stones. These stones are very consistent and aggressive, very good at bevel setting razors and knife sharpening. They originate from Yamagata but are no longer mined.

Kakishibu – 柿渋

Named after a traditional dying method using discoloration caused by the oxidation of fermented juice. It is a visual quality to certain stones characteristically identified as a whiteish background color with circular or round blotches throughout in a light to dark brown variety. This pattern can form the look of droplets or standing water on the surface of the white background. Most common in Suita stones.

Kamisorido – 剃 刀 砥

An older whetstone stamp used to indicate that the stone is graded specifically for razor user. These are typically hand-held pieces of stone and may often be marked Narutaki (indicated district not mine).

Kan or Kan Maki – 環巻

This team means Ring Roll in Japanese. A visual pattern in the stone which mimics the rings of a tree. This can be easily confused with the Mokume, Nenrin Hada, or Torato qualities of a stone.


A kamisori style razor with an asymmetrical grind which folds into straight razor scales.

Katakuchi – 硬口

Often translated as “Hard Mouth”. This term is used when describing the hardness of a very hard stone. Usually analogous to a 4.5/5 stone or higher.

Kane – かね

Another name for Gokudo.

Kanesuji – 金筋

This is an often reflective (but not always) hairline inclusion which is “toxic” to the blade. Typically these lines are made up of a mineral inclusion which is harder than the surrounding stone and can be felt by the finger or as the blade is moved over it. Care must be taken to check all line as when a stone is freshly lapped flat it is possible for Kanesuji to not be felt by the finger/blade until the stone is used some. If you feel a line indicating Kanesuji, you can dig it out with a nail.

Karasu – 烏

A term meaning crow in Japanese. This is a blue/black/white pattern in the stone which resembled crows in flight within a darkening sky and come from the Aisa layer of the Hon-Kuchi Naori Strata. Care must be taken with these stones as the dark “crow-like” spots can sometimes be toxic to the blade and must be tested. Often these stones can also include Kanesuji lines which should also be tested for. Light Karasu stones free of lines are highly prized and valuable.

Kawa – カワ

The “skin” of a whetstone, the hard natural outer surface of raw sediment.

Keppan -血斑

Blood Spots. This is a visual moniker for stones which have blotches of red swirls within them which looks like pooled or running blood. As with most red coloring (Aka, Iromono, etc.) this is most commonly found in Kiita or Tamagoiro stones.

Kesuji – 毛筋

Hairline inclusions which usually show as black or brown on the surface of a stone but are not felt under the finger or blade. Not to be confused with Suji which is a different formatoin in the stone. Kesuji can sometimes swell with soaking in water and crack along the line, so care must be taken with stones which have deep or plentiful Kesuji lines. It is possible but not common for Kesuji lines to become Kanesuji in different parts of the stone, so hairline inclusions should be frequently retested especially when polishing.

Kiita – 黄板

A term meainng yellow plate in Japanese.  These stones will be a vibrant or dark yellow throughout the base coloring of the stone as well as when the stone is slurried. The Kiita coloring can often indicate that the stone will be softer but that is not a firm rule. This is not to be confused with Tamagoiro which is a related and similar looking color. Often the difference between the two can be conclusively decided by looking at the slurry’s coloring rather than that of the stone itself.

Kiiro – 黄色

Yellow/Amber. Usually used to identify qualities of a stone but not the whole stone itself, otherwise it would be noted as Kiita.

Koma – コマ or こま名倉 

This term indicates Fine and is said to come from “Komakai” (Mr. Sakamoto). Koma Nagura’s traditional use is in sword polishing between the Chu Nagura and Uchigumori steps, but it also has a popular use as the last step in the 4-stone Nagura set used by people honing straight razors. Due to its use in sword polishing it is the most expensive of the Mikawa nagura. Some debate exists whether Koma is actually finer then Mejiro and necessary for razors. Most consider it a comparable fineness with Mejiro but has additional cutting power. This was stamped as こま名倉 on old Hatahoshi Nagura stones.

Kongo Do – 金剛砂石

Sandstone (Emergy) Whetstone. A very aggressive man-made whetstone used at the start of the sword polishing process or in other circumstances where blade geometry must be formed, or chips/damage must be repaired. These stones are extremely aggressive on the blade and remove metal quickly (for a whetstone).

Koppa – 小端

This term means small end in Japanese. It is used to refer to the end cutting pieces from larger stone harvesting which are then resold as smaller or off-shaped stones for a cheap price. People will often see these as razor stones but care must be taken to determine the quality of the Koppa before assuming it is a razor stone just because it is “hand-sized”.


A relatively unknown stone which is medium-fine, a bit rougher than Aizu.

Koukyuu – 高級

This term means Luxury of High Class in Japanese. It is one of the visual designator Kanji used on Mikawa Nagura. This one indicates a non-specific designation, indicating that the stone did not cleanly fit into one of the other 5 more specific terms. Typically these stones are mixed between white and striped making them not fit into any other terminology.

Kouzaki – 神前

One of the Tanba/Tamba mines in the northern Kyoto region, it was known for producing exceptional Aoto stones which were harder and finer than others. It also produced regular Awasedo stones which were known to be extremely good for razor finishing. These Awaesedo were often cut in razor dimensions (wide and short) and were usually a dark grey.

Kuro – 黒

Black. Usually used as a stone characteristic for Tsushima or other primarily black whetstones.

Kyoto – 京都 or 京都府

The modern name for what was once the Yamashiro prefecture, the actual city of Kyoto is also located within this area. This area is located in the western portion of the Kansai region.

Kyōto Tokusan- 京都特産

Kyoto Specialty Product. Often Kanji seen on boxed stones which are sold and originate from Kyoto, it can also be seen as stamps on the stone when they were not boxed.

Kyushu – 九州

The western most region of Japan and also its own island, Kyushu has a rich history in stone production and knife development. This area is known for producing coarser style stones such as Amakusa and Unzen stones.

Maruichi – 市印

This stamp indicates the Maruichi brand and is usually left in light or dark blue ink on the stone along with a variety of other Kanji stamped as well. Many think it indicates superior quality stones from Nakayama, though many known accounts of stones from the Narutaki mine sold with these stamps are known as well.

Tokusen – 特撰

Specially Selected Stone. This indicates that the stone is of good quality similar to other quality-oriented stamps.

Maruka – ㋕正本山         

Approved by Kato (Maruka) ㋕ Shouhonyama 正本山. This stamp appears on older Nakayama stones which were of high quality and is a call back to the original mine owner Mr. Kato. These stamps tend to drastically increase the stone and are frequently forged on stones. Far too many Maruka stamped stones are available for how long the stamp was used and generally, unless from a very reputable source, Maruka stamps should be treated as fake now adays.

Masame  – 柾目

A term meaning straight grain in Japanese. This is the resulting visual look when a stone is cut with the Gotogi layering on the sharpening surface of the stone rather than the more usual side orientation. This does not negatively impact performance of the stone and is simply a name for the look/style of cut.

Maruoyama – 丸尾山

A Nishi-Mono mine known for producing stones from Maruozan mountain. These stones are typically Suita stones and are known for fast cutting speed and soft composition. They also sell an Uchigumori-like product which is labelled Shikiuchigumori, though it by nature isn’t actual Uchigurmori it can perform similar. This mine is still open, and the mine owner will make special cuts to order.

Mejiro – 目白

A term meaning white eye in Japanese. This is a very fine Mikawa Shiro Nagura which is used as the last 3rd step in the 4-stone Nagura progression used by people honing straight razors. There is debate about whether this is finer than Koma or not. Most suggest it precedes Koma in the line-up as it is equally fine but with a lower level of cutting power (and thus theoretically more likely to make wire edges).

Mikawa Shiro Nagura – – 純三河白

A nagura traditional used in the sword polishing progression which was also made popular for razor use by Iwasaki-san of Sanjo. This white or stripped stone comes from the Aichi prefecture east of Kyoto. The stones perform differently than most other Aratoishi/Nakatoishi/Awasedo stones in that they have binder which plays a role in the metal grinding process but the actual grit in the stone itself is very smooth so non-aggressive. This combination allows the stone to still efficiently cut/polish metal without leaving deep scratches in the steel. Koma nagura was used for this property in sword sharpening after Chu nagura, and those same properties make Mikawa Nagura popular for knife polishing and razor honing (where the fine low-scratch capabilities result in an exceptionally refined razor bevel).

There are 9 usable layers that were pulled from the various Mikawa mines, though one of them (Tenjyo) there is no delineation between the two variants as they function similarly. The progression of different stone goes: Mushi ムシ -> Ban バン -> Atsu アツ -> Yae Botan 八重ボタン -> Botan ボタン -> Tenjyo 天上 -> Mejiro 目白 -> Koma コマ

More can be found here.

Mizu or Mizu Asagi – 水浅黄

A term meaning light blue water in Japanese. Usually, this term is used to describe a blue/grey color that is reminiscent of shallow ocean water. The color can also be greenish as well and is formed between Asagi and Kiita layers. These stones typically have a high percentage of grit within them and are very hard.

Mizukihara – 水木原

A Nishi Mono Kyoto mine and famous as one of the two mines which has access to genuine Uchigumori stones.

Mokume – 木目

Wood Grain. A pattern that resembles the grain found in wood. The difference between this and Kan is difficult to tell. This should be less layering across the stone and more of a pattern within it. 

Momiji – 紅葉

This team means autumn leaves in Japanese. This is a visual term indicating the look of colorful blotches of renge which are akin to fallen autumn/fall leaves on stone. Typically for this term to apply you should see multiple different colors of renge mixed together blanketing the stones surface.

Mushi – ムシ

No distinct translation. This is the coarsest layer from the Mikawa mine and unsuitable for use in any razor coarsest progression. It is more traditionally used for thick knives and tools.

Nagura – 名倉

This term originates from Sakon Nagura who lived in the village of Mikawa 700 years ago and was the first person to begin distributino of the Mikawa stones as rubbing stones. We now use this term Nagura to refer to a correcting stone – for correcting the surface of a stone or the blade scratches depending on context. A western term for a similar stone would be “slury stone”, though the word Nagura does have a wider meaning to it.

Nakado – 中目

Also referred to as Nakame. It means middle grain.

Nakatoishi – 中砥石

A term meaning medium whetstone in Japanese. Can also be referred to as Chu-Shiage Toishi. These stones are meant to erase the early deep scratches of Aratosihi and prepare the blade for the Shiage Toishi/Awasedo steps. Often, multiple Nakatoishi are used where you move from a coarser Nakatoishi to a finer Nakatoishi to further develop scratches. Functionally Nagura stone are also considered a “very fine Nakatoishi” but that can get confusing. Binsui and Aizu are probably the most popular nagura stones.

For a more comprehensive list check here.

Namito – 並砥 or 并砥 or 大上

The seventh usable layer in the Hon-Kuchi Naori Strata group, these stones have a reputation for being very fine and hard due to their high level of compression. Namito sits between the Aisa and Hon-Suita layers and is sought after for knife sharpening and razor honing purposes. These stones are less likely to have inclusions than other layers and are usually very pure. 大上 is the lower portion of the Namito layer referred to as Daijyo but is usually all lumped together under Namito.

Nakashiro – 中白 

One of the usable layers from the Ai-Ishi Strata. This is often just sold as a “Suita” stone.

Nakayama – 中山

A Higashi Mono mine which is the most popular Awasedo mine in Japan. Nakayama produced more stones than any other mine in the area (only rivaled by Shoubudani) and dug well below the water level in their mines. Due to this popularity some will discuss Nakayama as having superior qualities than other Hon-Kuchi Naori stones, but that is not the case. However, the larger production of stone did allow for better QC to be done, which means maybe on average there are more “good Nakayama stones” floating around than other mines. However, a good stone from any other mine can perform equally. None the less this reputation has driven the price and demand up.

Another item to consider is the cultural use of the word Nakayama. Similar to the Western countries’ use of the word “Coke” to delineate the majority of Cola products, this is often the case for Nakayama as well. Often a good honyama whetstone will be referred to as “Nakayama” it “performs as you would expect a Nakayama to perform”. This can be difficult for people who want to specifically ensure their stone is Nakayama origin.

Namazu – 癜

A term referring to the giant catfish of Japanese mythology responsible for creating earthquakes. When used with whetstones, it indicates a visual quality where white or very light tan marks in the form of spots, lines, nonuniform shapes are present in the stone.

Nan – 軟

Soft. One of the Kōnan-do Kubun (硬軟度区分) or hardness classifications.

Nari or Naori – 成り

This term refers to mountain geology and is functionally a synonym of stratum. Naori have multiple layers (also strata) to them.

Narutaki – 鳴瀧 or 鳴滝

A Higashi Mono mine which is known for producing fine grit hard asagi stone. The mines name takes after the region around Kyoto which is called the same Narutaki name. This can be very confusing as at one time boxes for stones from Kyoto/Yamashiro were labelled with Narutaki to indicate the broader area rather than the mine itself. If a box has Narutaki on it, almost always it is referring to the region and not the mine. A Narutaki stamp on the stone can be either or. When referred to as the region and not the mine, it will often be combined with Sho-honyama to say Sho-honyama Narutaki as the following Kanji 正本山鳴瀧.

Nashiji – 梨地

A term meaning pear-like in Japanese. This is a visual term indicating small brown spots or marks on the stone and looks very similar to a brown variant of Goma. These are non-toxic marks and do not impact performance of the stone.

Nihon kamisori-yō – 日本剃刀用   

A term meaning for Japanese razor. This stamp can be seen on old-stock stones (usually koppa) which were specifically cut and boxed for use as high quality razor stones.

Nishi Mono or Nishi Mon – 西モン

A term indicating West Side Mountains in Japanese. These are mines that are positioned west of Mt. Atago. This is sometimes referred to as Nishi no Yama 西の山.

For a more comprehensive list of these mines check here.

Nenrin Hada – 年輪肌

This team means tree-ring skin in Japanese. It is used to describe a pattern within the stone that looks like the growth rings of a log or tree. The entire circle of the “log/tree” should be present or else this attribute is called Kan.


Also sometimes called Numata also sometimes called Tora-to. A mine closed in 1965 from Gunma prefecture. It is finer than other stones from Gunma.


Oversided Stone. This is generally used to refer to Koppa of Nagura stone, mostly Mikawa stock.

Ohira – 大平

Sometimes written as Oohira. A Nishi Mono mine with a reputation for outstanding Suita stones. This sotne also have a huge place in Japanese sword culture as it produces the best Uchigumori stones for sword polishing practices. This mine is still active.

Okudo – 奥殿

A Higashi Mono mine which is known for producing Suita of the highest quality. Due to this reputation the prices of the products have increased and there are many unknown Suita stones being sold as Okudo so care must be taken when sourcing one. This mine is still active.

Okunomon – 奥ノ門

A Nishi Mono mine.

Omura – 大村

Sometimes written as Oomura, these are sandstones which come from the mines in Wakayama. There are multiple varieties of Omura stones which include the standard version, Suisa (finer), and Chameto (coarser).

Otoyama – 音羽山

A Nishi Mono mine known for producing Suita.

Ōuchi – 大内

Sometimes written as Oouchi, this is a Nishi Mono mine known for producing soft stones similar to Takashima stones. These are known to be very porous and thirsty stones.

Ozuku – 大突

A Higashi Mono mine which is known for producing very hard and very fine stone. Ozuku stones are sought after as razor hones and tomo nagura stock.

Ozaki – 尾崎

A Higashi Mono mine.

Renge – 蓮華

This term means lotus flower in Japanese. This is tiny freckling in the stone that can range in colors such red, orange, pink, purple, black and blue. Black and Blue Renge is often referred to as Kuro or Ao Renge. Not to be confused with Goma or Nashiji, which will be clearly dots rather than various shapes. These are non-toxic and do not impact the performance of the stone.

Saeki – 佐伯

An early level Nakatoishi stone which is very coarse and soft, analogous to around 800 grit. These are rather rare to find on the market but unfortunatley can contain particles which cause rogue scratches so care should be taken.

Saijōkyū – 最上級

This is a stamp on whetstones which refers to the stone being extremely high quality of superlative.

San  -サン

San refers to the dimensions the whetstone was originally cut, and typically refers to razor hone style cuts around 200 x 50mm in size. These cuts often came from the left-over end pieces of larger mother-stone blocks which were cut down into regular bench stone sizes.

Semai- 狭い  

A term meaning narrow in Japanese. This usually is used to refer to the thinness of a stone.

Senmai – 千枚

The fourth usable layer in the Hon-Kuchi Naori, this comprises of only 2 layers and is the thinnest of all the different strata. Sometimes compared to performing as a mix between Suita and Tomae as it sits between those two layers, it is also often a fairly compressed, hard, and fine stone. Though it may have Suita properties in the stone face feeling silky/soft, it tends to be fairly hard and not lend itself easily to polishing work – instead being better for sharpening knives/razors. Due to how thin the layering was, it is very rare to find large stones from this stratum.

Shiage To or Shiage Toishi – 仕上げ砥石

A term meaning Finishing Whetstone in Japanese. Sometimes this is used as a synonym for Awasedo, other times it can refer to a softer/coarser Awasedo in the 3-4/5 hardness area. One of the Ryūdo Kubun 粒度区分 or Granularity Classification.

Shin Tsū – 普通

Common. One of the Kōnan-do Kubun (硬軟度区分) or hardness classifications.

Shinden – 新田

A Nishi Mono mine which is known for producing exceptional quality Suita. This is often lumped with Okudo as the best Suita to get. The mine is no longe active. Finding good pieces of Shinden can be very difficult and when you do they are often expensive due to demand. The stones are often very white with noticable Suji layering on their surface.

Shiro – 白

White. This can be used to refer to the color of the entire whetstone itself, or sometimes is used to refer to only a section of the stone if the coloring is included with other base colors.

Shiro Suita – 白巣板 or 白巢板

This term can either refer to the 9th and deepest usable layer in the Hon-Kuchi Naori or to a Shiro-colored Suita stone. This can be confusing for individuals specifically looking for Shiro Suita strata stone as Shiro colored Suita does not only come from Shiro Suita strata. All Shiro Suita strata stones though are white however. Care should be taken and the stone should be sourced from a reputable vendor to avoid confusion and mistake. These stone are known for being hard Suita stones that dish slowly, cut quickly, and polish well. Those qualities make them very desirable, and price follows accordingly.

Shiroto – 城所

A Higashi Mono mine.

Shouhonyama or Shou-Honyama or Sho-Honyama or Shohonyama or Shōhonzan – 正本山

This team means original mountain in Japanese. This stamp can be found on finishing stones. Modern use of the term refers to Awasedo sourced from the Kyoto area. Sometimes a version of this is written as 正本山木格品 where Honkakuhin (Authentic Product) is added onto the end of the phrase. This can become confusing as digital translators sometimes will turn this into Masamotoyama or Seihonzan which is incorrect. Similarly it can be written 合請純正本山 which translates more literally to Ukea Junsei Honyama (Genuine Original Mountain).

Sikiutigumori/Shikiuchigumori – 敷内曇

Clouds on the Floor. Similar to the Karasu pattern, but instead of angular crow-like shapes it will have a cloud-like appearance within the grain.

Shiki Tomae – 敷戸前

The fourth usable layer within the Ai-Ishi Naori. Usually this is just called Tomae along with the other Tomae layers of Ai-Ishi Naori when sold.

Sō or So – 層

A term meaning stratum in Japanese. Different from Naori in that it references the specific layers within the broader “Mountain Geology Strataum” rather than the broader geological event. The multiple layers in the Hon-Kuchi Naori are each a single Sō layer.

Su – 巣

A term meaning nest in Japanese. Su is a visual and structural classification to a stone where small holes are present in the formation of the stone. These holes were formed as gas moved through the sedimentary material as it was undergoing metamorphic changes, these escape routes creating small holes within the stones surface. This is most commonly found in Suita strata stones, however Tomae and other layers can infrequently have them present. If a stone has Su holes extra care should be taken if following a nagura progression as sediment from the nagura can get stuck in the hole and dislodge during later stages of your sharpening/honing/polishing progression.

Suita – 巣板 or 巢板

A term meaning Nest Board or Nest Plate in Japanese. These stones are highly sought after and are known for being very fast cutters while maintaining a high level of fineness to their abrasive. Suita stones can originate from the Tenjyo Suita, Hon-Suita, or Shiro Suita stratum when referring to the Hon-Kuchi Naori. Suita commonly have Su throughout their structure but there are versions which have no Su holes called Sunashi Suita.

Suji – 筋

A term meaning muscle in Japanese, this can sometimes be mistranslated as logic or streaks. This is a visual and structure quality to the stone which shows itself as brown lines running through the stone, often grouped together around layering divides. Not all Suji is safe to the blade, and stones with Suji present must be tested. Often the thicker the Suji line the more likely it is to be toxic.

Sujimono – 筋物

A term meaning muscle matter in Japanese. This term refers to a stone with a large amount of Suji present running throughout the stone. Sujimono stones are often considered undesirable stones due to the fact that Suji can be toxic.

Suminagashi – 墨 流 し

A term meaning ink flow in Japanese. These stones have an ink on marble effect that is very beautiful and sought after. Often these are asagi stones with black lines/formations upon them, but the effect can be present with any color variation.

Sunashi – 巣なし

A term meaning no nest in Japanese. These are stones from one of the 3 strata of Suita which lack the common Su holes throughout its composition. Sunashi Suita stones have a reputation for being harder than Suita stones with Su present.

Tōken-Yō or Sword Grade- 刀剣用

A term meaning for swords in Japanese. One of the six visual grading stamps used on Mikawa Nagura which indicates the color and shape of the stone. In this case, it indicates that the stone is of exceptionally pure quality (usually pure white) and of a large enough size to use for sword polishing practices. These stones are especially sought after and are considered the highest quality.

Tamago or Tamagoiro -卵色

A term meaning egg colored in Japanese. These stones often look like a lighter less bright yellow version of Kiita, a yellow leaning tan base color such as a light-colored brown egg. Often it can be difficult to tell these apart from Kiita stones, but the slurry will often make it clear if it is Kiita or Tamagoiro. Tamagoiro stones tend to be softer.

Takao – 高雄

A Nishi Mono mine.

Tajima-To – 但馬砥

Also called Tajimado. Medium-level Nakatoishi whetstone. Not very popular around Japan but a very good whetstone from Nishihama, Mikata, Hyogo.

Takashima – 高島

A Higashi Mono mine which is known for producing very soft whetstones. Compared to other whetstones as soft, the fineness is usually above average. Often Takashima whetstones have oblong holes running throughout their surface like very large Su.

Tamahagane – 玉鋼

Iron Sand Steel. A traditional type of steel used for sword in Japan and smelted from locally sourced iron sands. Some classic Japanese razors will be marked as having this steel, though not entirely accurate (see Yasuki Steel below).

Tamamoku – 玉目

A term referring to the tamamoku cedar in Japanese. This type of wood has circular burls running throughout it which creates a specific visual look. Tamamoku when referring to whetstones are stones with base coloring which mimic this cedar pattern. Stones with this coloring are often hard stones which are highly compressed.

Tanba or Tamba – 丹波国

A term which means Tanba Province in Japanese. This was an area north of Kyoto and separate from old Yamashiro where whetstones were pulled from, the most popular being Aoto stones.

Tengu-to – 天狗砥

A term which means tengu whetstone in Japanese. This is a designation for a type of Amakusa whetstone which is usually stripped and red, but can also be a lighter red, white color and are always coarser and fast cutting.

Tenjyo or Tenjyou – 天上

A term which means heaven in Japanese. This term can be used to refer to Tenjyou Suita, or Tenjyou Mikawa Nagura. When used by itself it is most commonly associated with the Tenjyou Mikawa nagura. Tenjyou nagura are a medium level nagura and the second step in the 4-stone Nagura set used by people honing straight razors. There were two strata of Tenjyo but they functioned the same and are not delineated like Yae Botan and Botan are. Tenjyou is a fantastic all-around Nagura and can be used equally for tools, knives, razors, and polishing purposes.

Tenjyo Suita or Tenjyou Suita – 天上巣板 or 天上巢板

The second usable layer of stone on the Hon-Kuchi Naori and most popular for its Uchigumori stone. These stones tend to be very soft and fine stones, and the Tenjyou Suita strata did not run across the entire Hon-Kuchi Naori making it more rare than other layers. There are four levels to the strata which are uchigumori, nagagumori, sotogumori, and amagasumi (similar look to Sikiutigumori/Shikiuchigumori).

Tenjyou Tomae – 天井戸前

The fourth usable layer within the Ai-Ishi Naori. Usually this is just called Tomae along with the other Tomae layers of Ai-Ishi Naori when sold.

Tennen Toishi – 天然砥石 

A term meaning natural whetstone in Japanese.

To – 砥

The kanji for whetstone in Japanese. Usually used in conjunction with another word to designate a type of whetstone such as Tajima-to (a Tajima Whetstone).

Togidoro – 砥泥    

A term meaning grinding mud in Japanese. Often this is referred to as “black juice” or “stone juice” when translating. In english we normally refer to this as swarf, where the slurry and ground metal flakes mix together into a dark near-black mixture of mud.

Tojiru -閉じる

This term refers to the pasted made with Uchigumori powder (Uchiko) when mixed with water. This could also be made by generating a slurry ontop of an Uchiogumori stone for a similar purpose. It is used in later stages of sword polishing but can also be used in knife polishing progressions as well as one of the final steps to refine the definition of the steel.

Tokusenhin – 特撰品

Special Selection. This is another quality stamp found on stones to indicate above average performance.

Tomae – 戸前 or 户前

The 5th usable layer on the Hon-Kuchi Naori and where the vast majority of Awasedo originate from. This is because the layer is comprised of 48 different levels compared to the next largest layer (Hachimai or Namito) with 8. It is found between the Senmai and Aisa layers, and is known for having a very wide range of performance. In general, Tomae stones are considered a little softer than the other non-Suita varieties and have a very usable fineness to them. However, due to the vast amount of stone that came from this layer it is hard to draw any real conclusions in a broad sense, always test the stones!

Toishi – 砥石

A term which means whetstone/hone/grindstone in Japanese. Typically indicates something used after the initial grind is set on the blade.

Tokkyuu – 特級  

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

Tokkyujou – 上特級

Superior High Grade. One of the six visual grading stamps used on Mikawa Nagura which indicates the color and shape. In this case, it refers to a stone which has a striped base coloring with a square/rectangular shape to it.

Tomen – 砥面

Grinding surface. This is used to refer to the sharpening face of the stone itself.

Tomo Nagura – 共名倉

This term is used to refer to a companion nagura or “nagura sharing the same name” more literally. This is a nagura you use on a whetstone which is the same material as the whetstone itself. To be a tomo nagura, the nagura must be cut off the whetstone itself or from the same mother block the whetstone was sourced from. The use of this generates slurry of all the same type. Often this term is used to refer to a “Tomo-ish” nagura, where the stones are not from the same origin source but “perform similarly”.

Torato – 虎砥

A term meaning tiger whetstone in Japanese. This term refers to a whetstone which is red and color and has banded orange and/or white strips throughout, like that of a tiger. This is most commonly seen in Amakusa and Natsuya stones and tends to indicate superior grinding performance but at the expensve of relative fineness.

Tsushima – 対馬

A nagura stone which comes from the island of Tsushima, off the west coast of Nagasaki. When compared to other Nakatoishi is it on the fine end of things, but when compared to other Nagura it tends to be a bit coarser than the Mikawa/Chu options. These are very nice consistent stones that are soft without being too soft and abrade quickly. The slurry does become finer with use, but will never quite achieve the same scratch-less haze of the Mikawa options when used in bench format. There are generally two version, one called “Ocean” as it was mined underwater and is a deep black color with the other being a much more rare and less fine “Mountain” version. The mountain variety has an almost terra-cotta color to it and functions more like an early Nakatoishi stone than how we typically think of a Nagura bench stone to perform.

Type 30

A Type 30 Japanese natural stone indicates a minimum size of 205mm (L) x 75mm (W) x 30mm (H).

Type 40 – 四十型

A Type 40 Japanese natural stone indicates a minimum size of 205mm (L) x 75mm (W) x 25mm (H).

Type 50

A Type 50 Japanese natural stone indicates a minimum size of 180mm (L) x 82mm (W) x 30mm (H).

Type 60

A Type 60 Japanese natural stone indicates a minimum size of 195mm (L) x 70mm (W) x 25mm (H).

Type 80

A Type 80 Japanese natural stone indicates a minimum size of 180mm (L) x 63mm (W) x 20mm (H).

Ukeai Junshou Honyama –  請合純正本山  

Guaranteed Genuine Nakayama. This stamp can be found on the top of Nakayama whetstones, usually ones that are older. One of the commonly forged stamps now though.

Uchiguimori – 内曇 or 天上巣板 or 天上巢板

One of the levels which comes from the Tenjyo Suita layer in the Hon-Kuchi Naori, this is a stone critical to the traditional sword polishing process and Japanese culture broadly. This layer of stone does not run equally through the Hon-Kuchi Naori mines and is only present in Ohira and Mizukihara. Ohira is considered to produce the superior version. Uchiguomri is delineated into two versions, the soft (Hato) and hard (Jito) varieties.

Good quality Uchigumori has the ability to bring out banding from forged Tamahagane that no other stone can compete with, and it is a highly coveted stone for this reason. Compared to other stones, it tends to be softer than you would want for sharpening but can be exceptional at kasumi finish or polishing purposes. However, its performance is going to be similar to a good quality Tomae or Suita stone for non-Tamahagane or non-Honyaki blades, and as such the cost to benefit ratio tends to not be there. Due to its link to tradition and demand from traditional Togishi, these are very expensive stones.

Uchigumori Hato – 内曇刃砥         

The soft variety of Uchiguimori which is used to bring out details in the Ha of a sword/honyaki blade. This is also the most commonly sought after type of Uchigumori for San-mai knives as it will leave a deep hazy kasumi.

Uchigumori Jito – 内曇地砥

The hard variety of Uchiguimori which is used to bring out details in the Ji of a sword/honyaki blade. This is not usually sought out for San-mai knives as the stone can tend to be scratchy for soft cladding.

Uguisu – うぐいす

A color term used for Maruoyama stones indicating grayish green-brown ones which are mined in the Tomae layer.


From Gunma, it is a medium-fine whetstone similar to Tajima-to.

Umaji or Umajiyama – 馬路山

A Nishi mono mine which is known to produce soft stone which is a decent replacement to Hakka and similar to Hideriyama.

Umegehata – 梅ヶ畑

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

Unzen – 雲仙

These whetstones are quarried in Unzen, Kyushu. They are very similar to Amakusa whetstones and fall between the red and white versions of those stones. It suffers the same issue of an uneven grain structure. This mine is still active.

Uroko – うろこ

One of the layers from the Ai-Ishi Naori strata. This is often just sold as “Suita” stone. This variety is usually a bit harder than other Ai-Ichi Naori Suita stones and has a mottled brown pattern.

Wakasa – 若狭 

A whetstone mine which performs similar to the Honyama stones from Kyoto but instead comes from Miyama Mountain. They range in performance and are generally considered an inferior stone, though good examples of course exist.

Yaginoshima – 八木嶋  or 八木ノ嶋

A Nishi Mono mine located in the Tanba/Tamba region known for producing good soft Suita stone.

Yake – 焼け

A term meaning burnt in Japanese. This can either refer to the entire stone itself, but more commonly to parts of the stone which appear to have been “burnt” and show as a deep orange color. This is a very common quality in certain Suita stones, specifically Okudo. The quality however can show in stones from any strata and is also frequently seen in Senmai stones. In rare cases Yake can be harder than the surrounding stone and as such a form of toxic, so it must be checked (the darker it is the more likely this is the case).

Yasuki Steel – ヤスキ鋼

YSS is a special designation given to specific steel types produced by Hitachi. Some razor manufacturers have referred to these steels as ‘Tamagahane’.  I have to assume that this was done, mostly, during a period of time when very little real Tamagahane was being manufactured. While YSS was created using the same iron sand, it is not Tamagahane steel; it can be White 1/2, Blue 1/2/Super or Yellow Paper steel. Because Yasuki/Yasugi steel is made in Japan, it is referred to as Nihontetsu 日本鉄 . 

Yae Botan – 八重ボタン   

A term meaning double peony flower or eightfold peony flower in Japanese. This refers to it being the “second” or double Botan layer, as well as the eight usable Mikawa layer in the mine. This is a medium-coarse Nagura quarried at Mikawa which can be used interchangeable as the first step in the 4-stone Nagura set used by people honing straight razors for Botan. Compared to Botan the binder is a bit rougher and can take longer to mellow out with use but is functionally the same “coarseness” afterwards. This layer can have sand inclusions and pockets in the stone must be checked.

Yuge – 弓削

A Nishi Mono mine known for good quality soft Tomae stones.

Yūryō Shiageto  –  優良仕上砥 

A term meaning excellent finishing whetstone in Japanese. This stamp indicates the stone is a razor level stone and of exceptional quality.