Habaki material

[BDreier]

Hello All

I am writing to ask why it seems that all newer swords and production models have brass habaki, but all to many old swords have copper and gold foil overlay. Is the copper habaki weak compared to the brass?

Regards

Brian Dreier

[nagamaki - Franco]

Hello Brian,

 

Where structure is concerned, it would not be a matter of weakness. As long as the habaki fit is correct and tight on the sword and against the tsuka (seppa, tsuba), there are no metal strength issues, beyond being already damaged in some manner. That is why all the softer metals are seen, even in solid form. More than likely brass would have been a selection based on availability, economics (vs. gold), and/or simple matter of taste.

 

Regards,

Franco

[Ford Hallam]

Hi Brian,

 

as Franco has pointed out, strength is not really a consideration here. The preponderance of brass habaki on so called production swords is due to the fact they are frequently cast. It is extremely difficult to cast copper and quite tricky to cast fine silver too. I should also mention that traditional Japanese brass is somewhat softer than standard modern brass. New brass contains about 30% Zinc while older Japanese material contains about 15%, plus a tiny amount of Lead, about half a percent. The older stuff also patinates to a far nicer colour, a lovely ochre colour while modern brass tends to an olive yellow/green.

 

The traditional ( and more skillful and appropriate ) method of forging a piece of suitable ( ie; malleable ) metal to fit a particular sword will always yield the best results. It takes time and skill ; time = money so standard cast items are used.

 

I suspect that Franco may also have a point when he suggests that taste may be a factor as well, polished brass does look a little like gold, to the uninitiated . A bit flashy perhaps but there is no accounting for taste .

 

Of course if you really are concerned about strength then you can always get one made in iron. I've seen Kamakura period habaki like that. :D

 

regards, Ford

[BDreier]

Thank you for your response. I wanted to get more information as to what I have thought was correct information but as I do not know everything still learning.

Regards

Brian Dreier

roninswords

[Keith Larman]

Just to add to the discussion... Copper work hardens. Meaning (in general terms) that when the piece is forged to shape the material develops internal stresses which increase the hardness level of the material. So while dead soft copper is pretty soft, if the habakishi is doing it right by the time the habaki is properly fit the material should be pretty tough. And while most seem to think that habaki take no stress, the reality is that *in use* they do take some. Obviously it will make no difference at all if the blade is just stored in shirasaya and lovingly admired under a candle. But as a functional tool the habaki needs to be relatively tough to withstand some of the stresses involved in usage. Work hardening gets you there with materials like copper. And since you can easily anneal the copper as you work (it gets hard fast) it is an easy material to work with (relatively) as you forge and you have a lot of control over how hard it gets by the time you're done.

[Brian]

Keith,

 

Good points, and glad to have you posting here again. Nothing like hearing it from someone who has "been there, done that"

I also recall reading somewhere that the habaki plays more of a role than some of us may assume in the use and manufacture of a sword.

Good post.

 

Brian

[Ford Hallam]

hi all,

 

I would like to add that I am as yet unconvinced as to how any significant stress is placed on a habaki (or should that be, "an" habaki? :? ) The habaki "floats" on the blade, any impact absorbed by the blade and thus transmitted down into the handle via the tang may stress the wooden core, hence the need for the retaining collar of the Fuchi, but how is the habaki stressed?, to me, it seems to be by-passed.

 

Incidentally, if you consider the function of the fuchi being to reinforce the wooded tsuka, a but like a ferrule on a chisel, I would suggest that the opening in the tenjo gane for the nakago could be made to fit more precisely. This would then help limit the movement of the nakago in the wooden tsuka. It would also explain why so many really good fuchi do in fact have quite thick tenjo gane, but perhaps the original reason for that thickness has been lost in the mists of time.

 

One last observation, the only real damage (if you could call it that) that seems to be common on habaki is that sleight deformation around the bottom edge where it has been repeatedly bumped by loose fitting tsuba.

 

So, to re-iterate, if all the components have been correctly made and assembled, how does a habaki suffer any stress? If anyone could show me a convincing force/vector diagram I'd be happily "converted".

 

any scientists out there?

 

Ford

[Keith Larman]

In terms of stress, if you look at blades in use by martial artists frequently the mune of the habaki tends to get somewhat compressed. In extreme cases the mune of the habaki "peels back" at the corners with a complete failure of the habaki. Blades flex within the mounts during difficult cuts through stuff. A light cut on light targets is basically insignificant. And with hard tameshigiri training there can be significant force felt transmitted down the blades into the hands.

 

It is an extreme example but years ago Toshishiro Obata performed a kabuto-giri test. The cut was filmed with high speed cameras and the flexing of the blade was impossible to miss. That flexing on hard targets tends to push the mune machi into the face of the habaki.

 

And I've seen well made habaki made by Japanese trained habaki shi on shinsakuto that have been distorting similarly by those who do a lot of cutting. Well made habaki on well made blades that were themselves professionally mounted in Japan.

 

But vector diagrams... Sorry, not my area...

[Brian]

Just to back up a bit what Keith said..there is a bit of useful info here. You will have to weed out the non-relevant stuff and the info that is a bit fantastical..but some of it might be relevant.

http://forums.dfoggknives.com/index.php?showtopic=6300

 

Brian

[Ford Hallam]

Hi Keith,

 

thanks for that further comment, you've got me thinking on...

I've seen the Obata cutting test, he used an American blade I believe. Anyone know? I've also seen the same test performed using a sword made by Yoshindo. I must check that one to see if his blade flexes as you describe. I do remember the Obata sword flexing as you describe. Quite amazing really.

 

I also have the catalogue that the Tokyo National museum published in 1987, when they rounded up all the Kamakura and Muromachi mounted swords they could find. There are just over 100 uchigatana koshirae with blades, all illustrated in forensic detail. I assume these are the weapons that were actually used on the battlefield, this was certainly the premise of the exhibition. Just examining the photos of the habaki I can't find any evidence of distortion.

 

I wonder if this stress might be a new phenomena. Perhaps these practitioners of tameshi-giri are just too big and strong :D ,and are cutting too many hard things. :lol: I could also point out that this modern penchant for cutting things up and maintaining that it is somehow a legitimate samurai practice, may also be open to question. Certainly, the Shinkendo movement, which I think can safely be said to have be been developed from the training instituted by the Imperial Japanese Army in the last war, cannot claim any genuine samurai origins.

 

We all know that swords were routinely tested but I wonder why tameshigiri doesnt form any major part of any of the classical koryu.

I've wandered off the specific topic a bit but I think that these musings are legitimate points of discussion. Particularly as this forum concerns swords made and used in the past. I think we should be very cautious before we admit the experiences of modern practitioners, because it seems to me that what is being done today by tameshigiri adherents doesn't really relate to the past at all.

 

I may have to go into hiding for making such heretical statements about the value of tameshigiri, but these are only my opinions, If you don't like them...I have others!

 

cheers, Ford

[Ford Hallam]

Hi Brian,

 

just skimming through the thread you highlighted, the thing I picked up on was the dampening effect the habaki apparently has on a blade, and the fact that it is precisely the relative softness (compared to the steel) of the habaki that seemingly provides this effect,

 

this is all really interesting stuff

 

Thanks, Ford

[Keith Larman]

I'm not sure how examining the photos helps if we don't know if the habaki on those swords were work hardened or not. If they were, well, I'd say there you go, more evidence for work hardening being a positive thing.

 

And I'd also point out that koshirae on swords used in battle were reportedly remounted fairly often. So while a sword may have been used the various parts of the koshirae including habaki may have been replaced, perhaps even multiple times. Especially when blades are repolished due to damage in battle and remounted to be used again. You can be sure that much of the time the habaki was replaced at that time as well.

 

And I've seen poorly made habaki get ripped apart in "conservative" usage. One was a silver habaki that was pretty darned soft and it started "bulging" at the mune machi after a month or two of solo iai practice (no cutting involved -- well, nothing but air). I ended up making him a new habaki out of sterling silver and apart from the pain in the butt aspect of fitting it to his existing saya and tsuka I made sure it was work hardened by the time it was finished. That was about 5 years ago I think and that sword is still in weekly use with no problems. The original habaki fit properly and was flush against the machi as well as flush against the seppa. But it started to deform fairly quickly -- the blade it was on was an older blade that was pretty tired so I'm sure it flexed a lot. And the guy was a rather "robust" fella in his cutting style.

 

Regardless, I can only report what I've experienced and what I was told. I will likely see Brian Tscernega at Florida and if isn't too busy maybe I'll bug him about this one too. I think I discussed it with him once probably about 3 years ago when I was asking about working the piece a bit after the soldering of the seam and machigane... But I honestly don't recall. So I'll ask him again if I get the chance.

 

And on the martial arts end of things... Yeah, the Toyama Ryu fellas have had a profound influence on martial arts practice in the last 20-30 years. Increasingly so today. But remember that many koryu arts exist with a wide variety of styles and practices. And some forms of tameshigiri practice exist within many of them. The problem for some is that depending on when you were training you might see something like MJER or MSR iai styles as "representative". But frankly those styles are (in general) the more contemplative styles emphasizing solo kata without an emphasis on tameshigiri. As a matter of fact some sensei within some iai styles expressly forbid tameshigiri practice as being somehow disrespectful to the craft of the sword. But there are many styles out there from rough and tumble Jigen Ryu styles to the quieter, more subdued iai styles. I remember watching a Sekiguchi-Ryu (sp?) embu and noticing that their distinctive "Spin/Rap the sword" chiburi (don't have the name for it) really made their swords rattle. I wonder how many habaki they'd go through over time if the habaki was dead soft.

 

And FWIW take a look at any sword used by a martial artist. Notice the impression of the habaki face into the seppa. Seppa are copper and will often take an imprint of the habaki. The deformation is sometime fairly significant. Now consider the greater mass of the habaki and how much more material there is to compress if it isn't work hardened.

 

All interesting stuff. I'll ask Brian T about it next time I see him if I get the chance.

[Keith Larman]

Oh, and I forgot to add that one of my sensei trained in one of the smaller MJER lineages (the MJER lineage tree is *very* bushy). In general their training a couple decades ago was mostly individual kata cutting nothing harder than air. But once or twice a year they'd gather for a cutting session to validate their form, especially with some of the more difficult draw cut sequences. In their case they used certain plants. Others have used bundles of straw. These guys were not at all influenced by the various "WWII Imperial" training groups. Tameshigiri wasn't a major part of their training, but it was still a part of it. And while I know of major styles that don't do it and even some that expressly forbid it, most have it somewhere in the training.

 

But yes, some styles today have focused heavily on the tameshigiri component when in reality most would use it only as a sort of "check" on form done only occasionally and it existed only in a much larger framework. But it isn't like it wasn't done at all...

[Ford Hallam]

Hi Keith,

 

well you've certainly got me thinking. You are right of course, about blades being remounted frequently but the point of the exhibition I mentioned was that these swords were considered to be "straight of the battlefield", so to speak. Many in fact were offerings at shrines. And yes, we can't know if these are work-hardened or not.

 

I'm beginning to wonder though how much work-hardening can actually be induced when fitting a copper habaki. The kind of force that you have described seems to me to be pretty severe, enough to snap a blade at the machi area?, I know that this did happen. Could it be then that in fact the purpose of the habaki, apart from providing a nice fit in the saya, is to act as a sort of crumple zone. That is is designed to absorb those occasional severe impacts, the kind that modern practitioners seem to be subjecting their swords to as a matter of course. Could this also be the reason iron habaki were abandoned?, that the habaki was so stiff that the strain simply passed directly through to the mune-machi. At least with copper it can be absorbed somewhat. We know of the failure of many blades when faced by the Mongol hoards, perhaps part of the development after experience was the adoption of this "shock absorbing| collar, new and improved. :D

 

Do you think we could get "Myth-busters" to examine all the variables for us?

 

thanks,

 

Ford

[Keith Larman]

You should give Patrick Hastings a call about it. We've chatted about that one a lot and I *think* Patrick did some experiments a while back with the effects of work hardening on copper.

 

And keep in mind we're not talking about going fully hard in the work hardening. That will actually make the piece brittle. But some hardening is inevitable in the working of the piece and it takes very little to significantly increase the hardness of copper (and sterling silver for that matter).

 

I'll also point out that I'm not talking about a large, obvious issue here. But it is one reason why some swords develop "slop" in the fit of the tsuka very quickly. I have seen multiple "custom" sword mounts where the habaki had indented just a bit at the mune machi (and I assume ha machi). It wasn't really visible until you looked closely or removed the habaki from the blade and looked at the imprint. But once off it was obvious where the extra movement came from. And if the sword is being used for even just iai "air cutting" that bit of "slop" in the fit translates into vibration and an increased rate of wear and tear to the tsuka shitaji. When everything is tight all parts become a larger "whole". No play, no movement. Hence no vibration to cause problems.

 

Just a small bit of work hardening from dead soft to around half hard will significantly reduce that. Basically the notion is that fully annealed is too soft. But partially hardened is in general hard enough given the forces involved. So if we're talking half hard even rather enthusiastic use will be much less of a problem. And normal use is no problem at all. Fully soft? Well, on a sword being used even just for iai you might start to see a little rattle in a few weeks or months.

 

It's all about keeping the entire rig snug and tight.

 

But drop Patrick a line. I've talked with him about it many times and he's done a lot of fooling around with the effects of work hardening on copper in his shop practices.

[Keith Larman]

And on Mythbusters. I saw those guys trying to cut one cheapo production sword with another cheapo production sword. I don't think they know enough about the real deal to even begin on something as arcane as this... But I love the show anyway. Some nights its me and the 6-year-old sitting on the couch eating popcorn watching those two loons try things out. Now *thats* my dream job...

[John A Stuart]

Hi Keith and Ford, As you've brought up myth busters I must say that I found the destructive testing of those production swords quite illuminating. I was thrilled to see how large the angle of deflection could be before failure. It showed without a doubt how blocking a strike with the flat of the blade at an angle was the best way for a sword to take impact with minimal damage. It was the first time I had seen a strike made upon ballistic gelatine and was surprised at the result. I believe it was 9 inches. Of course those were socal types. How it relates to real nihonto would be pretty close I think. Anyhow, interesting. John