Sharpening Instead Of Polishing

[Prewar70]

When you use a knife, it dulls, and naturally you sharpen it.  There is obviously much discussion regarding polishing, and sharpening is part of the process or an end result.  I have not seen anything on the subject of sharpening for sharpening's sake alone.  I was wondering if anyone has information on this practice?  I'm thinking of ancient times, when swords were used.

[Brian]

Polishing is how the Japanese sword is sharpened. Appears they have never been sharpened any other way.

[Jussi Ekholm]

Search for netaba-awase. Warriors knew how to sharpen & fine tune their swords back in the day.

[Shugyosha]

In his book on tameshigiri Markus Sesko suggests that sword testers would take a polished sword and use what might be described as a proprietary method of sharpening the blade.

 

A bit like preparing a straight razor ahead of shaving.

 

Also, there was a famous sword called "beard cutter" because when the user took off the head of his opponent it cut his beard off.

 

Down to the conjecture bit, but that blade must have had some work beyond a normal polish. Also, it would be odd if people who fad lived around swords all their lives didn't know how to iron out minor defects in the cutting edge and render it fit for battle.

 

Jussi, I tried Googling the search term but it didn't help...do you have any links?

 

Thanks and kind regards,

John

[Fuuten]

 

In his book on tameshigiri Markus Sesko suggests that sword testers would take a polished sword and use what might be described as a proprietary method of sharpening the blade.

 

 

 

I get this post by darcy with some quoted parts:

 

"Almost forgotten today, netaba-awase was a serious issue for the old samurai. Many of them prepared their blades before entering battle because realigning the cutting-edge meant not only a sharper blade but it also extended the time before it had to be completely resharpened."

 

http://www.militaria.co.za/nmb/topic/14944-yari-marks-on-walls/

[Dave R]

I am getting some interesting results using this search term. "netaba-awase".

[Randy McCall]

Certainly "stropping" on leather or some similar material --   to pull and realign the cutting edge where wear has caused the actual 3-50 micron ha to become bent back or beaded --   is something often seen in modern knife sharpening.  A set-bevel of  approximately 30 degrees is stropped at the base of the ha, creating a finely tuned edge.  Today, this would generally be done after each use, similar to the sharpening of a straight-edged razor for shaving. 

I use a similar technique prior to, and after, tameshigiri with modern cutting blades (shinken) for iaido. This is not sharpening, but simiply realignment of the cutting edge.

It's not something I would even think of doing for nihonto

 

An old blog article I wrote (mistakes and all, with video resources) may be of some interest... http://www.tameshigiri.ca/2014/01/07/razor-edged-how-sharp-is-sharp/

[SwordGuyJoe]

Really interesting blog Randy! The video was great.

[Dave R]

Many thanks for the link, I am enjoying a tour of the whole website!......

  On another note, this photo below is often touted as an IJA officer sharpening his sword, but he may just be cleaning and oiling it. Interesting anyway.

[Gasam]

HI,

 

I saw in one of the countless movies about making of Japanese swords one interesting bit: when the warrior was called out to battle, they sharpened the sword in a specific manner (it was even demonstrated), whereas the edge was moved rather (i thought) brutally along a wetstone. It appeared they did this only once on each side. This was to prepare the polished edge for battle if I recall correctly. As I recall, the edge became a little coarser, but better for long time between sharpenings. If I could only recall the film. Will try to figure out.

 

Cheers,

[Stephen]

interesting on how one chooses to hold his steel, i prefer steel down using downward strokes.

 

 

[SAS]

I learned to sharpen from my dad, who was a chef/baker and a whiz with a blade and steel; I learned to polish from observing  polishers and doing my own work on the blades I forged. Polishing at the end stages is similar to stropping, in that the very edge is being reduced and smoothed for a very efficient cutting edge. Since few art swords are being used for cutting, I have heard that some Japanese polishers do not even make the sword edge very sharp. However, by having a polished edge and body, the sword is made very efficient for cutting, as was its original purpose.

[Greg F]

Randy thanks for the good link. I. saw the stropping video a while ago and tried it out with some success. (Not with Nihonto of course) All the best.

 

Greg

[Bazza]

HI,

 

I saw in one of the countless movies about making of Japanese swords one interesting bit: when the warrior was called out to battle, they sharpened the sword in a specific manner (it was even demonstrated), whereas the edge was moved rather (i thought) brutally along a wetstone. It appeared they did this only once on each side. This was to prepare the polished edge for battle if I recall correctly. As I recall, the edge became a little coarser, but better for long time between sharpenings. If I could only recall the film. Will try to figure out.

 

Cheers,

 

G'day all,

 

Gasam, I believe the scene you mention is toward the end of this video:

 

The polisher is Sasaki Takushi.

EDIT: The scene start at 46.00 minutes if you you don't want to watch the whole video.

 

Bestests,

BaZZa.

[Mark S.]

The stone used seems extremely soft... almost chalk-like... although drawing the blade across any surface like that will cause wear.

 

Mark S.

[Carlo Giuseppe Tacchini]

Maybe pumice stone. It was and is commonly used for this type of sharpening here in Italy, and Japan has at least as many volcanoes as us...

[Gasam]

G'day all,

 

Gasam, I believe the scene you mention is toward the end of this video

 

The polisher is Sasaki Takushi.

EDIT: The scene start at 46.00 minutes if you you don't want to watch the whole video.

 

Bestests,

BaZZa.

Heyas,

 

Thats the one yes :-)

 

Cheers,

[Mark S.]

Maybe pumice stone. It was and is commonly used for this type of sharpening here in Italy, and Japan has at least as many volcanoes as us...

Pumice is usually very gritty... The stone in the video appeared chalky... almost 'soapy' when the blade was drawn across it sharp edge first and seemed to shave several small pieces off.

[SAS]

It looked like chu nagura, a middle stage stone used in polishing, to my eyes.

[Baka Gaijin]

Hi guys I used to have a copy the original big hardback Japanese language  book on Gunto Soho, Toyama Ryu and Nakamura Ryu by Nakamura Taisaburo (中村 泰三郎) published late 80's.

 

If I recall correctly it contained drawings for what could best be called a "Stropping Rig" .

 

The rig was designed to be made from timber with two adjustable screw points to hold the blade at a precise angle allowing the monouchi to be stropped.

 

I am pretty sure it mentioned it was not to grind metal but was to even out hakobore.

 

The source of much of the information in Nakamura's book was the original Rikugun Gunto Soho training manual, a copy of which is housed at the National Diet Library in Tokyo (I posted this link on another thread recently, but I think it got missed).

 

http://dl.ndl.go.jp/info:ndljp/pid/1460369?itemId=info%3Andljp%2Fpid%2F1460369&__lang=en

 

Note the HInged test Tsuka for Tameshigiri on frame 46.

[Taz575]

I saw the same YouTube video where they touched up the blade so it would have a more aggressive edge.  It makes sense because a highly polished edge may not bite well into whatever is being cut.  I sharpen my Japanese kitchen knives to different grits depending on what they are being used for.  Meat processing knives are the coarsest, veggie knives are a higher grit and high end sushi or stuff would be a much higher grit on a natural stone.  Gyuto or general purpose chefs knife get a 4-8K edge typically.  I prefer natural stone edges to their ceramic/manmade counter parts as even the finest natural stones still have a little "tooth" left to the edge. 

[Caleb Mok]

(no knowledge of historical practices below if that's all you're looking for)

 

Swords, which were hardened to below ~60 Rockwells, in some way made up for their inability to get as "sharp" as blades hardened harder by the fact that they reached much higher velocities.  As for the degree of the edge's bevel, we do know that generally speaking, the lower the angle, the sharper.  But the discussion brought up sharpness testing in addition to the general way of ~sharpening for sharpening sake~, and this i think will give a different way of looking at bevel angle, as well as other factors.

 

I submit my humble observation that when woodworking i'm interested at tools' ~overall~ sharpness between sharpenings, not just its initial, right-off-the-stones, sharpness.  The initial sharpness is meaningless to me in this: It quickly goes away and i am stuck with a "sharpness" that only dwindles, and depending on that bevel angle, the RC and composition of the blade, and the finish, it can dwindle at vastly different rates. The "sharp" tool for me then is a contest between  "the edge that gets real sharp but loses it quickly" and the so-called "the edge that doesn't get sharp and you're stuck with it a long time."  Well, ~how~ sharp? ~How~ long? The winner is the one with the better average score.  So bevel angle alone is not meaningful to me.  A white-steel blade that is very high in RC is a PAIN to sharpen and to increase the surface area that i need to sharpen by decreasing its bevel angle is too much work for me: for such a blade i'd prefer going higher grits to make up for its lack of an acute angle.  The opposite can apply to a soft blade.

 

With sword testing it was probably done with right-off-the-stones, initial sharpness.  It would make every sense that way.  Now let's consider the scenario that magnifies every factor EXCEPT the blade's RC: the cutting of very easily-cut things, like vegetables.  Here, a well polished and strongly acute bronze razor might do as well as a 67 RC highly-ceramic steel (i do not call them "highly-alloyed", but "highly ceramic", for that is what they are).  Now let's consider the scenario that magnifies ONLY the blade's RC: hand-scraping a hand-made saw's blank down to correct thickness.  Here, a highly polished blade might do as well as one not so highly polished AS LONG AS it is made of a high RC blade.

 

Now let's go back to sword testing.  It was on bodies, of flesh and bone.  Knowing that you CANNOT alter the RC, what are the only variables left?  The velocity of the blade, its finish, and the bevel angle.  I do not know about you, but i find that in sharpening my kitchen knives to cut stacks of 3"-4" pork chop stacks in one stroke, sharpening anywhere finer than Shapton Pro 2K becomes diminishing returns in terms of initial sharpness (Shapton 2K is finer than some brand's higher stated grits).  5K and higher is VASTLY superior in terms of sharpness retention* for me...but that's not what we're talking about here.  We're talking about one stroke, how many bodies; not many strokes, how many bodies.  As for cutting bone with a deba(yes, actually cutting, not crushing...even though in dispatching an opponent you need neither), i find that you can do whatever you want but as long as you push-cut you will certainly fail and if you draw-cut you are more likely to succeed--the more slanted the better.  Which implies a sword with more sori will carve through bone better.

 

Well there you have it: if you want a practical sword for mass-infantry tactics, you'll go with with a straight sword; if you want wonderful cut-testing results, go for the most impractically heavy sword you have and hope it's highly curved too.  You don't have to polish the blade that much: because if you swing it THAT HARD and it hits flesh, a finish equivalent to 2K or 12K wouldn't really be that different ON THE FIRST STRIKE; if you hit metal armor, it wouldn't cut regardless.  But if your sword is to hit things again, and again, and again, then...i'll be honest i have no idea but i'm biased to think the RC is the most important factor (even though i'm trying to exclude this factor here) but that's because i cut wood much more than food or my face.  Someone who cuts the latter, on the other hand, i'd imagine, if he/she is biased, would be biased towards higher grit. 

 

So my speculation would be, because it is PAINFULLY long to grind hardened steel with natural Binsui (either the modern white type with lots of impurities or the more rare yellow type with few impurities) or Arato, as opposed to aluminum oxide, the sword that had an acute angle, if needed to be sharpened quickly, would face the pressure to be converted into a blunt angle...and that sword will forever have lost its "maximum" sharpness until there's times of less war when it might be restored to a "correct" angle whatever it is (i have never read literature on this...only literature on niku...but niku can be changed).  The harder swords would be subject to a greater incentive to blunt their edges' angles; the softer swords would be subject to less.  Though it's impossible to speculate what angles koto, or any heavily-polished sword, may have had, we do have many Shinto-and-post swords that we can see have a rather blunt angle (well, from my experience anyway) and many sources say that polishers say Shinto steel is harder.  Again, without aluminum oxide, acute angles can take a really long time...

 

And as for the finish ie how high the grits go for use...probably not that high, which literature seem to agree on.  I remember somewhere they said they probably stopped at chu-nagura...but such a statement imho is meaningless.  I was told by a reputable source that kaisei is only slightly finer than binsui, but binsui is a HUGE family of stones of varying finenesses and hardnesses that share members with the amakusa.  Chu nagura, on the other hand, are usually not-hard. (just look at it, obviously very sedimentary at some point before becoming metamorphic).  The hardness and coarseness of the binsui/kaisei if urgency called for them would have made a very deep impression to the blade that the chu-nagura would take forever to erase.  Sorry i digress: just trying to say, i don't think we'll ever really know because it'd have depended on many varying cases of'urgency and they had a vast array of stones, and maybe even bevel angles if the steel was soft enough, to choose from to accommodate.

 

Lastly, from experience, it is impossible for me to match the sharpness of something sharpened parallel to the edge to that sharpened perpendicular or 45 degrees to it.  Yet we see consistent info regarding the 45 degrees to traditional Japanese chef knifes, but not Nihonto.  Goes to show that maybe, just maybe, they understood that apart from cutting tests, it didn't actually matter ~that~ much.  Now the artistic quality on the other hand, that's an entirely different story!

 

-Caleb

*I can elaborate on this but pls pm me... this has nothing to do with historic Japanese swords

[Dave R]

Polishing or sharpening?

[SAS]

That is a nasty looking stone, no one told him about flattening the stone?

[Baka Gaijin]

Hi Dave.,

 

The image of the Togishi you posted is believed now to have been contrived for the tourist portfolio industry.

 

If you don't have the link, here's the Nagasaki University Library collection of high quality Bakumatsu period photographs, it is quite comprehensive:

 

http://sepia.lb.nagasaki-u.ac.jp/zoom/en/index.html

 

I've put the filter here for Samurai and craftsman related images:

 

http://oldphoto.lb.nagasaki-u.ac.jp/en/list.php?req=2b

[Stephen]

It looks staged to me Steve, many from that era were.

[Dave R]

 Certainly posed, camera speeds were too slow for anything else. But who are the models, and where did the props come from? I doubt they used random bystanders, why bother when you could go to a workshop and get all you needed in one package.

[Stephen]

just my point of view, your welcome to disagree. we have seen many photos from that era with mismatched armor. Photos were new then, and tourist love to get photos taken. 

 

much like at amusement parks in USA

 

 

[Randy McCall]

On the togeshi picture, I had researched that before.  It is, at a minimum, officially staged... whether the craftsman / equipment depicted are real is a question open to debate.  It's known the photographers used both real craftsmen and actors for their photographs... whichever were available and physically appealing.

This picture is part of the collection "A Tourist's Album of Japan", photographed in 1909 by Katherine Wolcott and her uncle, Robert Hull Fleming.  The collection is presently housed (physically and in digital format) at the University of Vermont, Bailey/Howe Library, Special Collections. 

The collection description reads (bold is mine): 

"There are nearly 40 leaves of collected photographs and postcards, numbering two to three per album page. The pictures range in content, some depicting staged photos of daily life while others portray landscapes and countryside. The album itself measures approximately 11 x 14 x 4 inches and is currently housed at the Robert Hull Fleming Museum at the University of Vermont.
 

Wolcott’s album captures a unique view of Japan at the brink of burgeoning Western influence. After defeating the Russians in the Russo Japanese War (1904-05), Japan began to cement itself as a global power, and its efforts to modernize began to attract Westerners. The images in this album depict a Japan with a strong national heritage and cultural appreciation as well as a newfound embrace of modernization and technology.
 

Most of the pictures in the album sold commercially as a form of postcard."

Collection link:  http://cdi.uvm.edu/collections/getCollection.xql?pid=japanesetourist

Togeshi image direct link:  http://cdi.uvm.edu/collections/getCollection.xql?pid=japanesetourist&rows=1&start=81

The description notes that these postcards were sold in Japan -- where they were very popular -- as well as in North America and Europe, suggesting at least the staged portrayals were accurate enough to engage native Japanese. 

[Baka Gaijin]

Hi Guys.,

 

The Harvard database looks promising as it will eventually include complete albums from the periods in question:

 

http://hcl.harvard.edu/collections/epj/albums.cfm