Edge on Japanese style swords?

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Benjamin Liu

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Jan 26, 2000
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I've heard two main opinions on Japanese style sword edges. Many people use the term "3 ft razor blade" to describe them and say they should have cutting edges similar to those of knives and be able to cut with slight pressure. Others say it should be like an edge on a Kris Cutlery sword, one that can cut with the proper technique but not very sharp compared to knives. I have several Kris Cutlery swords and they work fine for me, but I'm just wondering what the edge on a real Japanese sword should be like. Thanks.
 
It's not really that simple...

Some swords were extremely sharp, some swords were not. It depends on how the sword was shaped and what you expected to use it for, along with the overall quality of the piece.
 
Ben Liu:

Edge geometry was often dependant on the era in Japan. In later periods where metal armor was used more extensively, the convex grind or clamshell grind were used on swords so they could shear metal. This edge piled more material behind the cutting edge.

The convex grind is the opposite of the COncave grind, or hollow grind, which reduced the material behind the cutting edge. The reduction dropped the weight, and an acutely angled edge profile is a slicer.

Eventually, spears and halberds all but replaced swords on the battlefield in Japan. They were still carried as close-in weapons, and as honor marks.

Keith
 
Just for additional clarification...

Concave edges were not used on Japanese swords. They were/are convex, though they ranged in degrees of convexity. The placement of the sword's "meat" also changed from sword to sword, sometimes a little closer to the edge (making the edge itself more convex) or a little further away (making the edge a little flatter). Depends on what the maker/buyer wants out of it.

Originally swords were not the predominant weapon in Japan. The spear and bow were more commonly used as primary weapons, with the sword being more of a sidearm usually. It wasn't really until the Tokugawa period (post-1600) when swords would begin to take the spotlight and become a more prominent status symbol.
 
the long swords (20"-28") either had a convex grind or a V-grind but with a thick, prominent cantle that served to strenghten the edge and provide an automatic sharpening bevel. the short sword (14"-18") was either convex-, flat- or even hollow-ground. It was really just a long knife for close-in fighting.

the really long battle swords (as much as 36") were often intentionally dulled but they can still be sharpened for dueling. miyamoto musashi's rival, sasaki kojiro, adapted a battle sword for dueling. he kept it sharp. unfortunately for him, musashi faced him with a stick that was at least 6 inches longer so when they clashed, sasaki's sword cut musashi's silk headband. musashi's stick smashed sasaki's skull.
 
Hank:

Cantle? I'm not entirely certain what you mean by that, but the sound of it seems like you're implying that swords had a secondary bevel (as knives do). They didn't. Again, Japanese swords did not utilize hollow/concave grinds. That seems to be as common as the whole "chisel point for penetration" idea.
 
yes, i've seen a lot of swords with secondary bevels near the edge but the main profile was either full-height V or convex. i've also seen a number of hollow-ground wakizashis (half-height). and in museums, looking at old guards (tsuba), you will see the cross-section of the swords by the aperture, since the grind goes past the guard and into the handle. for world war 2 officers' swords (they featured release buttons for the scabbard), the grind was full-height convex.
 
I'm sorry but I've never seen or handled a Nihonto that had the features that you claim. The "grind" goes all the way from the mune (in case of hira zukuri) or the shinogi (other styles) to the edge, no secondary bevel exists (which is why the edge is developed in polishing, not just stropped later). Also, I nor any other enthusiasts/collectors I've talked to in recent times have ever seen a hollow-ground Nihonto, or one with a secondary bevel. The only Japanese blades other than knives that I've seen with secondary bevels are low-quality mass-produced WW2 pieces, which are not considered Nihonto. Some of the mass-produced stuff in China also has hollow-ground blades and some with secondary bevels, but again that doesn't approach Nihonto, which I think was the focus of the thread. Another source may be what is sometimes advertised as iaito that come from the manufacturer with a mild edge and leaves it to the user to sharpen it him/herself. What comes close to looking like a secondary bevel is the old kiriha zukuri style, which is an archaic form on ancient pieces and only looks that way because the shinogi (ridgeline) is closer to the edge than it is to the spine.

Also, if you look at tsuba collections, you'd notice that the nakago-ana was usually not perfectly form-fitted to a sword. And, the vast majority of tsuba I've examined (I'm not a real enthusiast of tsuba, but viewing them is part of appreciating Nihonto) have not offered any evidence that they were used on swords with a hollow cross section.

If you can find any pics of a real hollow ground Nihonto or one with a secondary bevel, please post it because it would certainly be a rare and interesting find. However, I think that maybe you've received some questionable information, and the pieces you've seen may have been incorrectly identified.

(oh, if you want to browse through some swords, you can look at Aoi Art, they normally have a nice variety. By no means is it comprehensive to all time periods, but it's nice to visit, and they've always got nice pics. http://www.aoi-art.ab.psiweb.com)
 
Every high quality katana and other Japanese Tanto sword I've seen has featured a hollow or flat grind on the main edge and a Hamiguri or "appleseed" grind on the tip for better armor penetration on the battlefield. The appleseed grind puts alot more metal behind the cutting edge and therefore reduced the amount of edge deformation when going through the leather or steel armor depending on the era in question.

To see this grind combonation in practice look at the Spyderco Lum Tanto fixed blade or folder. they have the exact grind I speak of.
 
By "high quality" I assume you mean recent commercial manufacture. All of the blades I have and have handled, real old genuine Nihonto, have some hira-niku or convexness to the "grind" in the edge. Shinogi-zukiri, and Unokubi-zukuri especially have "meat" in the edge. Lots of the Hira-zukuri have the convex edge as well as more of a flat profile but never hollow. The tip or Kissaki has lots of Hira-niku or meat in the edge, especially the shinogi-zukuri style since that part took a pounding. I have a blade by Hizen Tadakuni which was a master in the early part of the 17th century and the blade is a perfect example of the Hira-zukuri type blade and even though its been polished a few times it still has some niku. Hamugiri I believe means Clamshell edge I think but I will have to check and that indicates a very fat convex edge. I have never heard of "appleseed". I have a big library so I can check. Its been a long while too.
 
Hey Guys,

As far as the modern tactical sword, there are two different kind of edges. One that will have a coarse edge because there is more metal backing. And the other will have a thinner edge around 0.043 thousandths of an inch used for slicing through fibrious material, flesh, plant material, ect. The thicker coarse edge model is more used for combat or steel to steel combat. Think about it, even though a sword might not be a "razor" 24 or 36" of steel can still do alot of damage.

Keep It Sharp,

Chris Bowles
www.bowlesknives.com
 
Originally posted by Robert Marotz
The "grind" goes all the way from the mune (in case of hira zukuri) or the shinogi (other styles) to the edge, no secondary bevel exists (which is why the edge is developed in polishing, not just stropped later).
Click to expand...
in kuzan oda's article, the sword polisher explained how swords were initially cleaned and polished using a progression of at least 8 polishing stones, all by hand and using water. after polishing, it goes to an EDGE SHARPENER.

sorry, no pics. but i'm sure my eyes didn't deceive me and the blades/guards i examined were certified pre-1905 pieces.

regards.
 
Im familiar with Oda. Having seen many pieces in fresh polish including some from Fujishiro I assure you the finished edge is done by the Togi or Polisher and also called sharpener and as a result of the use of the stones up to the Jizuya and Hazuya (finishing stones) which is thinned Uchigamori, to the final step using Nugui to get contrast in the hamon and ji. The result is a very very sharp blade.

Perhaps Oda was referring to the fact that smiths would often use there own set ot stones for initial line refinement and to get the hamon in view so that it could be assessed by the smith, then it would be sent to the Togi for polish and sharpening.

If I become a Gold member I will post some pics of my Tsuba and other Kodugu. I have tsuba in excess of 400 years old....with blades the same vintage.

Dave

BTW get the book "The Craft of the Japanese Sword" by Kapp and Yoshihara. Yoshihara is a smith that is considered a national treasure in Japan. The pics are great and it will tell you exactly how it is done...the traditional way.
 
Hey AKADave...you got any pics or oshigata of your Tadakuni piece? I'd like to see some more older Hizen pieces.

And you nailed it right on the head with the togi. While of course the shiage isn't totally committed to honing the edge, it sure can do a good job of it. :D

Oh and I second taking a peek at Yoshihara's book.
 
Hi, I do have oshigata but I cant post here but I can send pics. If you have Roger Robertshaws book on Hiznto then you can see a photo of my nakago in his book. Actially the blade is signed "Hizen no Kuni ju nin Hironori" It is one of his first pieces done about 1615 and has been authenticated. He signed Hironori first before changing his name when he got Harima Daijyo when he was 37. Its a 15 inch hira-zukuri wahizashi with bo-hi. Beautiful toran-ha hamon. Its mounted as an O'Tanto.

True about shiage, by that time its sharp as heck and it seems sharpness is an afterthought.

I actually checked out one of Robert Robershaws blades in fresh polish. It was a Shodai Masahiro that was a special order katana and it was believe it or not Unokubi-zukuri with 27-ish nagasa. Also to top it off it had a cutting mei! 2 bodies through the chest in one stroke into a mound of sand! You should never ever touch the blade with your fingers but he let me touch the edge and yes it was very very sharp. We had uchiko and oil there so it didnt get a stain. I loved that blade but he sold it for another aquisition. His collection of Hizento is very very good.
 
If you want to email them to me (rcmarotz@eot.com), I can upload them to my webspace and I can post pics from there.

Sound good?

And yeah, I've seen some of the Hizento materials, though I don't own any of them.

Hizen and Gassan are what I'd like to see some more of, but I won't complain about looking at Bizen and Soshu pieces ;)
 
Well, Ben Liu, There you have it. FLat grind or convex grind, disputed on the hollow grind. Choose wisely.

Keith
En Ferro Veritas.
 
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