Posted By Thomas L. Buck


Recently, I have seen an increase in requests for second peg holes (mekugi-ana).

 

Although one would think that two pegs would be better than one, at best, a second peg has no effect, and, at worst it can jeopardize the structural integrity of the tsuka and shorten the handle's life span.

During a study session, Takahiro Ichinose explained that on most long swords the mekugi-ana is around "3 finger widths" from the tsuba, which is the pivot point, or point of least stress during most cuts. The further away from the pivot point a peg hole is, the greater the strain on the peg (mekugi).

The only type of truely Japanese mounts that I can think of with two pegs are the Late War Type 3 Gunto (in a katatemaki pattern), see:  http://www.h4.dion.ne.jp/~t-ohmura/gunto_005.htm

 

It has only been  in the last 10 yeas that I have seena lot of "Japanese" (but not really) swords with two pegs.  All of them are modern reproductions like from Cheness and Bugei, or those coming out of China and Pakistan.

To illustrate this, I have included an old diagram scanned from my personal notes written back in `88. It outlines Mekugi-ana stress, and explains why a tsuka with one hole has fewer fractures, a longer life span, and is more reliable than a tsuka with two

.notes

 


Does this make sense to anyone aside from me? Why -or- Why not?

 


 
5 Comment(s):
bizzo said...
actualy guys this article in my opinion says one important thing look for 1 peg to validate the sword is real handmade the old way from japan. its important we support this beautiful heritage and art form. knwing things like this help to do so. the japanese made sword will is one that will last throught time when all other metals and forging weapons and fighting have been used up. these blades will be unchalanged. as a more than avid swordsman i know the value of these blades and this article only brought back to my attention that indeed 1 peg was always the original standard in japanese hand forged katanas. spread the word. its time we buy japanese!
January 11, 2013 12:58:22 AM
 
Blackthorn said...
Hi, I read your article, quite interesting, but I must say I don't agree with your conclusions. With only one mekugi, the thin edge of the tang will bear force to the inside of the tsuka. To calculate the force, it's just mass/area, so the smaller the area bearing the force, the higher the stresses there. If you also spread the load across the centre of the walls of the tsuka with a second mekugi, the forces now bear over three parts of the tsuka rather than one. Without a second mekugi, you'll more likely split the tsuka closer to the top edge, while with one there, it will split along the centre. The laws of physics don't change for Japanese swords, except in the movies, if force is distributed over a larger area, the pressure reduces. So, if there's enough force to split the tsuka across the second mekugi, there would be more force exerted on the upper inside edge with one, which would split it more easily. We have to be careful not mix up correlation with causality here. These two mekugi tsukas split because of the structural integrity of the wood, not because of the presence of the second mekugi. If the majority of two mekugi tsubas are made of substandard and/or overly thin wood, they split because the stresses exerted upon then exceed their load bearing capacity, not because of the mekugi. They would theoretically split more easily without the second mekugi, as the stress is more concentrated in one spot. Simple logic would dictate that if second mekugi caused tsuba splits, all (or even most) tsubas with two mekugi would split! they don't. Mekugi are not the cause of tsuka splitting, but since a lot of cheaper, badly made tsuka employ two pegs, they split because they are badly made tsuka - there is a correlation between badly made tsukas and two mekugi pins, hell, nearly every production sword has two, so some will inevitably fail, but cause and correlation are not the same. The only way to test this would be to carve two batches of identical tsuka and rig one lot with two mekugi, another with one, rig up a device to exert a measurable force, and see at which point they fail, and if there's a difference between one batch or the other. Otherwise, you are just speculating on the cause. Have you thought to ask yourself why late war gunto would use two mekugi rather than one? That would be the first question I would be asking? Did they find that the single mekugi failed so they added a second. I know that the military would not add anything extra, surplus, or unnecessary to a military issue item, considering resources, cost and production time. Why would they go to the trouble to make this change? Especially considering the Japanese obsession with tradition. If the Japanese banned early guns because it disrupted their social structure and the value of samurai, what would induce them to change the design of the very cultural and spiritual symbol of their nation that they have adhered to for hundreds of years. It would have to be pretty serious because any military changes in design are dictated purely by functionality, not aesthetics. Now I'm speculating, did single mekugi gunto not hold up against hardened steel barrel of a bayonet-fitted WW2 rifle in close quarters combat, so they had to update the design... Some questions which beg to be answered I think, what do you reckon? Regards
July 25, 2011 02:01:04 AM
 
Devin said...
This makes a lot of sense to me. So basically what I get out of this blog is that a single peg well carved tsuka is really an important feature for long lasting tsuka. While double peg might be good for a short term fix for a mass market katana tsuka, really one should carve (or have one carved) a new tsuka to match your nakago if you want your tsuka to last.
July 21, 2011 05:54:19 PM
 
Al said...
By the same token, if the fit is good the lateral stress on the second peg should be taken up by the tsuka, yes? The only time the stress should be transferred to the peg is if there is any slop in that fit. At that point it's going to elongate the peg hole in the tsuka and cause problems. That said, if you've got that second peg, you'll stop the end of the nakago bashing around in the cavity of the tsuka and making the slop even worse.
July 19, 2009 05:20:55 AM
 
Roman said...
The point is in problems with mass produced swords, where tsuka is not properly fit for nakago. That's where the second mekugi is truly needed. I there won't be one, there will be realy sensible play of far side of nakago in tsuka. That's why everybody is used to two mekugi. My opinion is there is no need in second mekugi if tsyka fits nakago well.
July 11, 2009 06:02:17 PM
 
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Thomas L. Bu...
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