Why develop a false edge on purpose?

Can a false or feather edge serve a purpose.

The back and forth strokes are the most common stroke used with tools and knives, and many razor honers do also use back and forth. This is a stroke that can be very good for you if you master it, so the stroke itself is not a negative issue. I use the back and forth strokes for plane blades, chisels, but for the final finishing I use edge leading strokes in order to reduce the development of a false edge.
My thinking and understanding is that when when two sides of a blade meet in perfect geometry the edge looks like a   V  , when they form a false edge it looks like a   Y  and a dull edge looks like a   U  . In my shop I will take a blade that is dull, develop a false edge on purpose, and then remove the false edge to create a sharp edge. So my sequence looks like  U-Y-V.
When I hone a razor or chisel I try to create a Y profile because the tail of the Y is proof that the two sides have met each other. Then I take that Y shape, remove the tail and I am left with a V shape which I consider to be perfect geometry.
In my studies I have found that on a high quality Awasedo with slurry a forward edge leading stroke will quickly remove the feather like false edge with just the first few strokes. To add more strokes on the slurry stone is not better and here is the reason why. A stone with slurry builds a wave of slurry in front of the blade (front of edge in edge leading strokes—-front of spine in spine leading strokes) and this slurry has thickness and great cutting powers.
The thickness of the wave and the concentration of the slurry component will abrade and slightly convex the bevel beginning at the edge before and with less influence back away from the edge with edge leading strokes. In other words the blade at the edge is more directly affected by the slurry first and before the rest of the bevel is affected. This makes the blade slightly convex and the edge. The more strokes you add with slurry the rounder the blade gets, so when you go to your clear water stage the bevel is not flat anymore and the edge sits ever so slightly a little bit above the stone.
If the edge is sitting above the stone when you use the clear water strokes technique, this will begin to reduce this curvature and eventually the blades edge will touch the stone as the bevels becomes flat again. The trick here is to know, or to be able to feel or see that exact moment when the bevel is flat again and as the edge begins to touch the stone. At this point in the sequence the geometry is acute and depending on the abrasive, and your technique the edge will be as sharp as it will get from that stone. Going next to a strop can add refinement too but if you final edge retained some areas of the false edge this edge can be slightly dull after the false edge is broken or abrade off.
Forward edge leading strokes reduce the area or band width of feather/false edge, spine leading strokes promote the width of the false edge, back and forth strokes do both. With the very last stone, just before you strop your razor I suggest that you do edge leading strokes only because they reduce the formation of a false edge and promote direct contact between steel and stone.
I suggest that you, with purpose, build an excellent and useful false edge with perfect geometry, and then manipulate your technique with slurry as your secret agent, the surgical removal of that false edge without overdoing it. If you can do this, in the end you are left with an edge of solid steel that represents your perfect geometrically designed razors edge.
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Example of the development of a razors edge.

The photos above are dramatic, they were created in my workshop with ordinary and common stones and they help to illustrate how a razors edge can be manipulated, and how it is manipulated whether you know it is happening or not.
The way I use a stone like the Okudo asagi is to make a diamond plate slurry lets say that looks like whole milk (not cream), and hone your razors bevels for how ever many strokes it takes to remove the previous scratches. It can be as few as 15 to 35 strokes.
Next I use a tomonagura  whole milk consistency slurry or slightly thinner, like skim milk for the same number of strokes. I always count so I know where I have been. To transcend to clear water I do this by when I am ready, I make a full pass with my razor and then rinse off the slurry that is on the blade in my water bath and I carry back to the hone the clear water that was left on the blade by the rinse. This water is now in play. I will do this several times until I am honing only on clear water. Then I strop 20x and test for HHT.
If I pass fine, I can strop more or test shave. If it doesn’t pass I will try 10 more strokes on clear water, strop and test, if still no HHT I try stropping 10 more times. If it still fails HHT I will go back and do a full bevel bevel set again and go through the whole routine but using fewer strokes at each level. I find that a razor can fail both HHT and Shaving Test if a false edge was developed and either broken off crudely, or it just folded over. I always felt that adding more strokes is not the only answer, a few maybe but not a lot unless your stones are totally slow cutting. If you are using fast cutting stone then more strokes just removes more steel when the problem might actually be 1) your technique is poor, 2) you have developed a false edge and failed to remove it through gentle abrasion, 3) you geometry was off from the bevel set stage.
The above assumes that you are using razor quality fast cutting stones. I have seen through my microscope what perfect geometry looks like, where the bevel setting scratches should lead all the way to the edge from the base of the bevel in long continuous scratch marks. If they do not reach the edge then the bevel is not set. If your scratches reach the edge as continuous scratches and you continue to hone a feather edge will develop but the razor does not get sharper and sharper after that point in time. If the razor did continue to get sharper the more strokes you add, then in theory the razor after 5,000 strokes would be sharper than after the first 1,000 or 100 strokes and we all know that this does not happen to be the case.
I feel that there are sweet spots in time at all of the razor honing stages of bevel setting, edge refinement and edge finishing which includes those final few strokes and stropping. The development of the edge can fail to configure at any one of these stages, and fail independently of the previous or following stage. If you keep this in mind and if you have a regular method you can reverse engineer your technique and begin to eliminate your technical errors.
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Symbiotic Stone & Steel

If you are going to work on razors and knives you will want a broader selection of stones, mainly because of the size of the knives and because of the necessity of an ultimately keen razor.

Razor stones are special because they are not only fine but they cut very fast, this is necessary because if they are not fine enough they will not shave well, and if not fast enough (highly gritted)  with the light pressure we use when honing razors it would take too long for each razor.

Knife stones are usually larger all around and will withstand a heavy handed routine necessary for knives, and knife stones are not normally as fine as razor stones because they first, do not need to be, and secondly the pounding and scraping that a knife edge goes through in normal use, a razor sharp edge will begin to breakdown within minutes.

You were asking about a suita for razors, maybe a pre-finish stone. Honing a progression of stones for razors is necessary for restoration from bevel setting stages on up. Some of us have a two stone progression and go from 1k  directly to a finishing stone, but many fellows use a nagua progression, a pre-finishing stone progression or even several stones lined up as a progression. I would suggest that a nagura progression that can include both Shiro Mikawa Nagura and or tomonagura slurry or elements of other stones would be considered to be the most professional standard. A progression establishes and maintains throughout the honing session an edge that is built on solid steel. The 1k to finisher does give a shave ready edge but it is so closely based on the 1k stones scratch pattern than there could be, in theory, structural factors that underlay that super keen edge that might create some jeopardy regarding the tenacity of the edge.

A single stone that covers all of the tasks of: bevel setting razors, pre-finishing razors, finishing knive edges should be based on a knife stone model if you take into account the factors from above. This stone would be a medium hard stone that in the 5 or 5- range, very fine in the 5 range, sized to fit the type of knife, and easily maintained so it can be lapped for razors when necessary. The grit richness that determines speed could be in the 5 to 5+ range. Sharpening knives is a heavy process that with the right stone can go quickly especially if the stone, like one in a hardness range of the lower 5’s is used because the stone is sheds dull used grit particles while revealing newer sharp particles.

This single stone could be a first step in building a flexible progressive stable of stones, one you could build around but it is unlikely that it will be your one and only middle range stone. I suggest that a tomae stone instead of a suita stone will feel the most comfortable under your razors and knives as “that single stone”. There is a page to my website that I have been developing but it is not yet linked to my website, it is devoted to knive stones and there is one stone there that you might want to try, #1103. This tomae is very smooth but cuts fast because it is grit rich but also medium hard. If you wanted to test it, with a deposit plus postage I could send both the  #1103 and the suita #1108.

Testing two stones side by side is very revealing, plus you have your Ozaki there already to test against these two others. I think it would be worth both of ours efforts to do this if you have the shop time to manage it in a week or 10 days. Each of the stones are priced and perform similar, and after testing you can send back one or both if you choose and all it will cost you is the round trip shipping in a Medium Priority box. I will always pay shipping for an outright purchase, but for testing the cost is on you. I have this same arrangement with a few other customers for different reason, but my main idea is to copy in my own way the way that these unique stones were retailed in Japan where the buyer/end user had a chance to bring his own tools or test his own razors on a group of stones to look for compatible combinations between his steel and their stone. The more you get into this the more you realize that with both natural and synthetic stone, there are symbiotic relationships between stone and steel. Almost any combination will almost always work, but combinations that really, really work well are special. The burden is on the stone to perform but the user is in the drivers seat, and when things click it takes a lot of stress out of the process and this allows the driver/user to not only get the same job done quicker but also allows him more flexibility to express technique and professional judgement calls.

Busy shops who specialize in particular steels or techniques find it efficient to match up larger stones that have a longer shop life with the normal tasks that are specific to their work. Blacksmiths choose the steel they forge, but they also choose the stones in their shop tailored to their favorite steels, and stones that are thick will have a longer shop life thus minimizing the burden of shopping for and testing replacement stones when their old ones get thin. Natural or synthetic is not the point, it is efficiency and quality that is primary. Not every stone works for every steel but for a smith or sharpening shop, they narrow down the possibility of failure or loss of production time by repeating past good experiences with certain combinations and repeat those over and over again. Like with antique Sheffield steel softer stones tend to work better and 20th C. German steel benefits by using harder stones. It can even fine tuned down to certain blade makers all though not usually necessary unless you are working with that bladesmith directly.

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The nature of Tomonagura and using a Diamond Nagura

Hello Tim

I do hope that you get the Okudo soon and that you like the tomonagura that I included. Without handling the tomo that you got from someone else, I wonder how mine would match up against the others. Mine might be just as soft so keep me posted.

Matching tomo requires having enough tomo samples to test with, and it is a little confusing too. In my own shop I relay a lot on a well worn Atoma #600 to perform the same work that some fellows use Botan and Mejiro for, refining the bevel after my 1k or 2k bevel setting stone. The diamond generated slurry is really fast cutting and I find it leaves the bevels in a very good state as the DN (diamond nagura) slurry crumbles from the bundled grit particles made from the DN down to smaller and finer individual grit particles. Using the DN slurry sets the stage for the tomo, and a tomo following the DN slurry has a much easier job.

The trick in matching a tomo falls into that narrow realm, picking out a tomonagura that does not deeply scratch the base stone, but is hard enough to abrade it slightly. Some of the burden on the user is to adjust his/her hand pressure, water content and stroke speed to prevent scratching. With really hard stones this all becomes more critical, and as a matter of fact the same holds true with honing really hard steels on really hard stones. As a purveyor of stones I often have to err on the side of a slightly softer tomo that demands less of the base stone as a slurry source, and this can seem like a miss-match, and I would have to agree if you had to go with your blade directly from the 1k bevel setter to the tomo and the base stone with no intermediate grit source. Going back to my shop, this is where the DN comes into play.

A DN slurry covers a lot of difficult ground when working with very hard stones, it is like a Botan-Tenjyou-Mejiro progression all in one slurry. I find that most users of Asano stamped Shiro Mikawa Nagura do not finish their razors with those 3 or 4 softer stones, they almost always finish with a tomonagura, and then often followed by a clear water polish. If accepting the proposition where the DN slurry can replace the Mikawa progression, then there is at alternate method leading to the tomonagura, and if the tomo has a ultra fine grit particle matrix that at least equals that of the base stone in fineness,  then in practice a slightly softer tomo can bridge that gap between the DN slurry and the clear water stage because the DN slurry has already relieved so much burden after the bevel set. This of course is all predicated that you have a super fine grit particle tomo.

I think that you will find the two tomo I enclosed in the package to be super fine, but as I began with they might be too soft to bridge the gap between 1k and clear water finish alone, if not try adding a DN element in there and see how that  works out. The diamond plate will have to have meet the same criteria as the tomo, one that does not leave deep scratches, so a worn out plate works best. If your plate does leave scratches I think that you might be surprised in the long run how little the negative effects actually are and that those same scratches might be worn down by the end of your honing session.

One more thing. It is cited that a diamond plate prematurely wears out a valuable on of a kind awasedo stone if you use it to raise a slurry. I would be a fool to suggest otherwise. But my choice to use a DN is based on balancing that tiny 50 microns thin skin of that surface sacrificed versus ignoring the superior cutting power of an otherwise very slow cutting hard stone that neither I or my son will ever wear out no matter if a diamond plate slurry is used of not. Almost everyone now used a diamond plate to flatten their stones, and then they just wash away that slurry down the drain. Many fellows flatten their stones before each use and wash away that slurry. If you do this, next time don’t rinse it away,  try using it.

Honing razors is really just a craft, and you can use the word compromise, or adjustments as an integral necessity of the craft. TheAxMethod pares down the stroke count, and treats both sides of the razor equally as a way of minimizing errors that are difficult to track down later. If you edges are sharp enough to shave with, than the ultimately sharp edge is just whispers away, maybe as few as 5 strokes more or less, pressure (more or less), or in the stropping. Focus on those instead of adding groups of 40 or 75 or a 1000 more strokes. The more strokes the better is not a true statement, if it was than 20,000 more strokes would still not be the ultimate. The truth is that these is a plateau in the number of strokes where the greatest and finest finish that any given stone will max out. The secret is to learn how to recognize this state of development, and to stop there and move on to another abrasive or another method.


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Musings: Wooden dai stone base

In Japan they often use Paulownia wood because it does not have strong growth rings with encourages movement with a change in humidity. This is a pithy type of wood and a similar one here in the west would be Magnolia. Balsa would be the extreme type of pithy wood but the strength levels are low. You need a wood that just strong enough so that it can be shaped but one that will not dramatically shrink or contract too much over the seasons. To adhere the stone to the dai I would just use some type of Latex caulking which bonds well enough while not being so permanent in case you decide to release the base and the stone.

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The Odori mine was near the town of Takayama which located in the mountains between Nagoya and Toyama. The name of the mine owner is Yamamoto-san, he is 87 years old now and is retired and he closed his mine a few years ago although he had not dug for the last 20. As a young man he worked in other mines before he dug his own, and Yamamoto-san also worked as a wholesale stone dealer who delivered and sold stones on a monthly route that included some travel on a motorcycle to barbers and carpentry shops. He has been my mentor for about 8 years and he and his wife live in a small town near Nagoya.

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Back and forth honing strokes

Hello M.
 One suggestion I have if you are developing harsh edges is to not do the back and forth strokes but to only do one direction forward edge leading strokes. When you sharpen with spine leading or back strokes this can promote an exaggerated false or foil edge. A foil edge is just like a wire edge but it is not rolled up like a wire edge is.
In a basic sense, sharpening is creating friction between the stone and the steel. When we want to control the friction so it works for our benefit, the most effective change in the blade at the edge is accomplished by edge leading forward strokes. The back strokes-spine leading strokes do sharpen but not in a positive way and more  haphazardly so we have less control over the outcome. Ask yourself, how much work would it be to hone a razor only with spine leading strokes?  Think of it like driving a car going forward, when you put on the brakes the inertia of the car creates a nose dive of the front edge as the car deals with the friction of stopping. Now if you drive that same car in reverse and put on the brakes the back or rear end of the car (the spine in our case) dives down towards the pavement. This still stops the car but all of the energy was exerted on the back tires or our spine of the razor. We do not shave with the spine, only the front or edge.
For a straight razor blade as in the car above going in reverse, the spine recieves all of the benifit of the friction where it is lost as far as the cutting action is concerned. The front cutting edge is still engaged and is abrated to some degree but the steel is not altered or fashioned in a positive direct way. Sharpening is a task, a thoughful action to refine a blade using kinetic energy. It takes effort and we choose the media and the method to craft an edge so in this sense we should use all of that positive energy and direct it on the cutting edge and its formaiton. To me spine leading strokes are wasted energy and because their affect on the blade is minimal, the task performed by those strokes are the unknown or variable factor and are best eliminated unless you have a logical reason to perform them.
A stone is attempting to sharpening a razors edge from the first stroke, especially if the bevel is fully set all the way to the edge, and each stroke is a contributor to that goal which is to create is a geometrically sound edge shape. This edge shape is usually thought to be either wedge shaped or slightly convex shape. The convex shape adds more meat, thickness or body just behind the actual cutting edge thereby giving it strength and tenacity to hold up under the work of cutting hair. The weakest edge is a concave profile shape where the cutting edge protudes like a tongue out and away from the body of the blade and has less thickness behind the edge. Think of it graphically as the difference between a wedge type razor and a hollow ground razor. Which is stronger? A wedge shape edge is stronger than a hollow or concave type edge.  In a concave shape the space between the actual edge and the thicker body of the blade, there is found to be a thinner area of steel. This gives the working edge a concave profile. This edge shape can appear to be very sharp at first but under a workload can break apart and become ragged and dull. This is a harsh edge.
Spine leading strokes promote these weak edges because when under abrasion circumstances. When energy is transfered from your hand through the steel and into the stone in the form of a kinetic forward/downward motion energy, the greater friction (abrasion) energies are delegated to the spine where it is wasted, while the minimal lesser portion of friction energies are relegatd to the following cutting edge. These lesser downward trailing energies encourage the formation of a very thin steel tongue at the cutting edge to remain intact because it just flops or folds back during sharpening instead of being honed off.
In razor honing or other fine steel edge creation there are always fragments of steel that flop at the edge of the blade because they are just moments or milimeters away from being abraded off, stroping can remove them.  The higher quality steels with high carbon content usually have a finer granular make up, white paper steel is a good example. Alloy steels like blue paper steel have hard additives like cobalt which are usually larger particles and these add endurance to the blade. The fine high carbon steels will sharpen to a finer degree but because of their finer grain will promote a false edge or a burr and this is very thin,  if you have finer abrasives to wear the burr or false edge of without breaking it off prematurely then I encourage this before stroping.  Faint slurry mixes or just clear water can aid in removing by abrasion these fragile steel fragments that have very little structure holding them together before going to the strop.
Hope this helps,
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Hello J.

 Here is a video I made of a finishing technique for finishing with water only.


About the pressure when honing. This is going to be the one thing that is individual to you alone, we can all use similar stones but the hand pressue will always vary from person to person. All I can suggest is that to develop a steady pressure that comes natural to you, that you can repeat without even thinking about it. I would think that most everyone uses a lighter pressure at the end of a honing session on a particular blade, the weight of the razor is a term used but this is up for individual interpretation as it would be hard to actually measure as the blade has to be controlled to some degree. I do lighten the pressure at the later stage but maybe not as much as others. Most of my videos are about stone speed and performance. I am not a real honemeister as I mentioned before. The razor I honed for you was just a foundation edge that was done quickly, I shave off all of these edges but they only tell me how the stone performed from stone to stone. I am only testing in a controlled sequence how one stone compares to another and not how I can fiddle with or add on to that sequence to make the blade the sharpest. I have to reject some stones because they do not cut fine enough or fast enough and TheAxMethod is my way of weeding through my inventory.


The video I sent you of honing in a pond is a variation of honing under running water at a sink, the idea is to minimize the effect of slurry, ie. loose particles. With a good stone this should create a keener edge because only the imbeded particle’s exposed portion with their lessor abrasive actions are affecting the blade, and these promote shallower scratches. The weight of the razor finishing stroke does this same thing, that of minimizing the cutting power or action. This is all based upon the a edge that is already 98% developed and can already shave. Our skin is so sensitive that we can feel the difference between a highly refined edge and a slightly less so edge. You can read of fellows who spend up to an hour honing with very light pressure in an attempt to polish the bevel, the whole bevel, thinking that it will be sharper. It might be but it is really only the edge that shaves, not the flat of the bevel.


Did you get a 1k stone for Xmas? The diamond plates tear up these hard thin steel edges quite a bit, and the agressive nature of coarse abrasives in general leave fractures into the deeper body of the razors bevel that create weak steel. A 1,000 stone leaves the edge weak also so for long lasting tenacious shaving edges it is best to have a progression of stones or a progression of nagura stones that lead into you final stone, healing the edge by gently removing material so the edge is based on solid virgin steel. You can achieve an excellent shaving edge with just one stone skillfully used, but a progression of abrasives will lead to a stronger edge that will withstand the pressures of continious stropping and shaving.


The honyama type stones found near Kyoto are known to be made of an abrasive of decomposed radiolarian chert. Chert as a mineral has a nature of cleaving and at these microscopic sizes the weight of a razor and or the tumbling of the chert in a slurry seem sufficent to pressures that encourage cleaving. The garnets in the Coticules will crush but I believe that the pressures necessary to crush or fracture them are greater than those exerted by a razor under what we would consider normal honing conditions. There are advantages to either of these abrasive compounds of course, and both will work in developing an edge sharp enough to shave with if the skill of the user is able to coax them to. Almost anyone with some history in useing these stones will claim that one stone in his collection works better with this or that steel over the others. Fineness, abrasive content, binder materials all factor into the equation. This is our quest, to match up with our own developed skills those stone and steel combinations. Buying more and varied stones can make some difference, but the real jumps in performance in regards to the abrasives will come from your technique in using them.


Good luck, Alex

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Some history and thoughts on the mine structure of Kyoto

The Awasedo Bearing Mountains of Kyoto
This is a diagram posted on other websites used as an example of the structure of the stone layering found in the Kyoto area mines.  Click on the drawing to make it larger.
The above drawing is very misleading because it shows an over simplified layering that would only appear if the mine is dug on level ground or at the very lowest elevations near the valley floor (no mountain slopes). And it makes the mountain look like a is built of solid layers of awasedo sharpening stone material.  There is a handful of remaining active modern mines producing traditional awasedo toishi that are in the Tamba region which is farther west of Kyoto City, or to the north/east of Kyoto near Lake Biwa and one or two small operations in the Yamashiro area. These are all  lower elevations mines so this drawing would be a decent description for those mines except that the mountian shape is too pronounced. I will refer to the output from these current mines as modern stone because this example of the stone layering structure has little to do with all of the old higher elevation mines that were closed before or just after World War 1  in the Yamashiro area of Japan, where the really great stones came from which I will refer to as historic stone
The current mines harvesting stone appear roughly geologically as depicted above only if you take into consideration that the actual full thickness of the total mine layering structure of all these stone stratas represented above is only about 50 feet thick, total. Those stone layers all neatly are stacked up on top of another are in correct order showing Aka-pin, regarded as the softest stones at the top, on down to Shiro Suita as the hardest at the bottom.  What I am going to do is to logically explain some of the differences between modern and historic stone:  why some stones are harder than others, why some stones cost more, why stone mined 100 years ago even look different than stones currently mined.  This article will hopefully explain why there are vast differences between stones at all price points and from all mines from the two eras, 1200 to 1900 and 1900 to 2014.
 The best of the best mines are already closed and the best of the best stones have already been sold. This is an harsh statement at face value so allow me elaborate.
The first mines in the Yamashiro area of Kyoto were founded and developed about 800 years ago. Although the record of the first discovery in 1190 lacks some detail it, largely concerns the presentation of the stone to the regent in Kyoto for his inspection and approval and that we do know that it eventually resulted in the creation of the title “keeper of the mine” for the finder Honma Tou-zaemon Toki-nari. Later in 1230 the title also granted the holder some exclusive rights to mine the stone on the site of the original discovery.
The name Yamajiro in kanji means Mountain Castle or Mountain Fortress, a classic plan for embattlements based on a Chinese model. The name Yamashiro-no-kuni was first used by the Emperor Kammu (reign 781-806) , it was he who moved the seat of power from Nara to Kyoto in 794 (establishing the Heian Period) to describe the lands surrounding Kyoto, his palace as the center of the city and the realm.  This is a more pertinent interpretation because it refers directly to the ring of mountainous area and the plain to the sea. The name Yamashiro was used through the Edo period, the area is now called greater Kyoto area. So if you see ink stamps on stones or stone boxes with the name Yamashiro-no-kuni this is the historic reference. This area of rural Kyoto was the realm of the Emperor but he portioned off areas for his retainers who in those days developed fortified retreat and place of worship for the various Buddhist and Shinto sects who in those days of civil war and strife were occasionally called upon to defend themselves with arms. but they most likely were in purview of the Emperor to some degree. These mountainous lands were and still largely are owned and maintained by those very same sects, and the locations of the historic mines that we hear so much about; Nakayama, Shinden, Okudo, Ohira, Narutaki, Ozaki and the 20 or so others were established on those private properties.
From the very beginning as far as I can tell the mine operators have been basically leasing the mineral rights from the religious sects on a year to year basis, not actaully owning the land. As a matter of first hand knowledge I know that the lease of one current mine is based on a what we call “a handshake” with the dollar value mineral rights lease equaling more or less that of an expensive bicycle.
The first sharpening stone found in the Yamashiro was most likely just picked up by Honma Tou-zaemon Toki-nari as a loose rock, and likely that event occured on the crest or a ridge of Mt. Shobudani. At the higher elevations of these low windblown mountains the rock lays bare, is easily seen and exposed to the elements while at the valley floor and up mountain sides and into and through the tree line there is as much as 40 meters of topsoil and plant life to dig through before you can find the vein of awasedo. This is why I think it is logical that the first walker who happened upon the sharpening stone material just picked up a loose stone. His next step would have been to locate the source vein of the stone.
It is recorded that the earliest mines were dug at the higher elevations were the mineral vein broke through the surface and was exposed. Over the next eight centuries the mine tunnels were dug at successively lower elevations as the stone stock was depleted or panned out in the tunnel above. The trick was for the miners to track and relocate the vein as it threaded its way down through and along the interior of the side of the mountain, lots of test tunnels were necessary over the years. The mine tunnels established were and still are set with narrow entrances, the tunnel dug horizontal and slightly inclined to facilitate removal of stone. Where the tunnels intersected the awasedo stone sheet they were hollowed out to look like large rooms as they were worked from side to side across the face, not deeper into the interior of mountain.
The stone deposit for awase toishi mined in Yamashiro appears within the mine geology as layers, these layers or strata are called in Japanese as Sou, and the sou are stacked like the pages of a book being back to front to back and so on. The book in this case is not laying down flat on a table but instead is standing up so the sou run vertical along and up and over the face of the mountain. Because of this, as you enter the mine tunnel you will be walking through and past each layer as they are stacked as vertically as the mountain is steep. If you go beyond the awasedo mine geology, the sou, you will hit the solid bedrock or the core of the mountain. So think of it as the stone layer with the awasedo being like a shield or skin over the mountain core.
This shield, if all were bare of vegatation on and around it would now look like a scab or patch as it lay on the mountain. Although as it was formed millions of years ago as a flat sheet of sediment, when it was scraped off the Pacific Plate as it reached Japan this flat sheet became in some areas distorted and torn into patches as in the Tamba Terrane and in other nearby places rolled or folded as in the Ultra Tamba Terrane. Also because the mountains beneath the sheet were still rising and forming, this vulnerable sheet was torn and seperated into isolated pieces or patches even further so that the indigeneous rock shows promininently between the patches.  The drawing below illustrates such a patch as it lays below the suface of the surrounding mountainside and topsoil material.


Between the various layers of useable stone are original occurrence deposits of waste material that is not suitable for sharpening stone called Gokume, where the gokume meets the awasedo some of it is retained and then it is called Kawa. These good layers of stone are anywhere between 6 inches to 2 feet thick with the grain of the stone running parallel to the layer. The waste gokume is usually several inches in thickness and of variegated darker colors of rough hard material. There are about 80 distinct strata that make up the mines geology in the Yamashiro area and the total thickness including the waste runs to or slightly more then 45 feet thick.
The mineral deposit that represents the body of rock dug for sharpening stones is interchangeably called awase toishi, awase-to or awase-do, and it lays like a shallow patch or scab that runs up and over and around the low mountains of Yamashiro in a generally westerly direction out and beyond the city limits of Kyoto. This patch is known as the Tamba Terrane and the Ultra Tamba Terrane. This same layer or terrane of rock in several different configurations extends somewhat further in all directions, but the stone found in the outlaying areas is not of the same superior quality as that found in the Yamashiro area located in and around the small town of Umegahata. The accepted center marker for the whole mining region is the peak of Mt. Atago and from there the divisions between the eastern or Higashi-mono, and the western Nishi-mono mines are defined.
Because the Tamba Terrane and the Ultra Tamba Terrane were scraped off as a accretion wedge during the subjection of the Pacific Plate as it dove under the Asian Plate, these mountain surfaces were formed from more ancient seabed material dating to the Triassic and early Jurassic periods a couple hundred millions years ago. The terrane as it lays forms a covering over both the valleys and peaks of the area.   Clicking on the Drawings below will enlarge them. 


This drawing below shows a conception of the compaction ratio of the same thickness of several layers or sou of mineral as it is compacted by the gravity of the enormous of the weight of the mountain side above.
 As you can see the weight of the mountain and its vertical slope should have a direct relationship to the compaction ratio of the metamorphic sedimentary stone that the Tamba and Ultra Tamba Terrane is composted of. In the very steep regions and at the lower elevations the clay binders of the awasedo stones are forced to compress. This compression along with any heat created by friction are other factors in the metamorphism of the silica, radialaria and clay components of the stone that makes up the awasedo stones of the Tamba Terrane in and around Kyoto.
Another important factor in the Tamba Terrane is the introduction of free flowing ground water at the lower elevations that can carry disolve minerals. Because of Japan’s unusual amount of moisture from rain the watertable levels can be quite elevated about the valley floors. This intrusion of water can disolve some of the original minerals such as found in clay and introduce alternate minerals, or may just remove those water soluable minerals all together leaving voids that are subject to compaction.
I am not a geologist, that must be apparent, but these simple changes that have occured in the nature of the awasado stones structure are well known. These are some of the main reasons why that the stone harvested from the mines like Nakayama and others was in the early days from about 1390 to 1860 of a softer consistancy in general: because it was dug at the higher elevations, and why the stone harvested durning the modern era from around 1860 to present is of a harder nature (unless it was freshly harvested at a higher elevation in a new mine discovery, however none are known to exist) because it was all dug at the lower elevations including below the watertable at the valley floor.
The modern era great wars that Japan fought  including;  the Sino-Japanese of 1894, invasion of Taiwan, Russo-Japanes war, WW1, then the 2nd Sino war of 1937, WW2 were devistating to the mining community of Yamashiro because if it were not for these wars and the demand for abrasives, most of which were used to hone the swords which most soldiers still carried in some form and the housing and rebuilding booms after WW1 & WW2, we might still have freshly harvested awasedo from the upper reaches. But this is not so. Almost all of the mines in the Umegahata area were closed before 1930 and the rest soon after due to depletion, the stone was all dug and trucked off. One of the last mines, Narutaki was finished off with steam shovels at the valley floor and bull dozed closed for good. The Nakayama mine itself was,  in a ditch last effort, below the watertable in 1965, and the nearly verticle mine shaft had to be pumped as they worked. There is even a photo of Kato-san in the mine wearing a raincoat and rubber boots. The stone from that tunnel, or more correctly, shaft, were ink stamped by Hatanaka Toishi Company with rope and tackle logo to signify that the stone was lifted up from below, much of this stone was useless.
Japan, the land of the largest and oldest wooden buildings in the world, of woodworking guilds that extended unbroken  for 500 years, of blacksmiths that created some of the finest swords in history which were all sharpened on natural japanese stones, of modern woodworkers who compete to shave with their handplanes continuous wood shavings in the 4micron range. These men and women had access to those stones. Why now are the mostly tourist oriented stores in Kyoto and Tokyo filled these days with hard, harder and hardest mostly gray stones?  Because they are leftovers.   Why are colored stones like yellow kitta, iro tomae for purples, reds and greens and white suita so rare and expensive? Because the crafts people in Japan hold them dearly.
Now I hope the users of natural japanese awasedo will have a broader perspective on why, when, where and how the current state of mining and selling these treasured beauties stands right now. There are still some old timer stones out there, and just like the vintage mined Coticules of the 1880-1910s the character of these stones is well worth digging for.
best wishes, 


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Blacksmiths marks on kanna blades

Hi Correy
     Good to hear from you, I am convinced that things are going well with you, and suspect that you have created a lifestyle that is a blend of the homey backwoods and a cool little business community.
     The little blacksmiths mark usually found at the top right of a kanna blade ura side is called a Bonji, a small personal mark that can be stamp or hand engraved into the metal which some blacksmiths use year after year or may even be passed on through multiple generations.
      A lot of people do not know this but bonji is one of the Sanskrit alphabets called Siddham that was transmitted to Japan through China in the early Buddhist eras of around the year 800.
     I became more aware of this when I brought one of my samuri swords for examination to a traditionally trained sword polisher by the name of Hayashi Shigekazu-san who before he unsheathed the katana took a long moment to pray to it. A non-Buddist would not necessarily do this but as you know Buddism and Shintoism suggest that spirts can reside in or as objects. So you will find in the sword world a certain reverence, and the bonji is an acknowledgment of that culture which also spills over into the tool world where many of the older blacksmithing families like Ishido-san were sword makers who continue  to attatch to their bonji as a tie-in with their past ancestors and as a show for the reverence of their craft that directly ties them to their ancestors.
     I see the bonji as used by a craftsperson as an acknowledgement of an influential force beyond his/her own powers to craft an object.
                         I hope this helps somehow, Warmly yours, Alex
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