Mekugi, the real secret of Japanese blades?

[Peter Bleed]

About a year ago at a local gun show I acquired a “Chinese polearm.” It was a boredom buy since I really have neither interest nor knowledge of Chinese weapons, but I think this is of a type that is commonly called a ‘Dao’. It came with no history and truly can be described as “in relic condition.” It sat quietly in a closet until last week when I began thinking – yet again – about “Namban sword guards” which, of course, includes a great range of Southeast and East Asian, European, and Japanese fittings that were re-purposed, traded, and variously mixed. In thinking about that topic, I decided that the best element on the Dao was its lobed guard that seems comparable to “early” Japanese tsuba. The flow of arms between Japan and China is well known.  To study that fitting, I set about disassembling the pole arm. I assumed that experience with Japanese arms would offer a basis for this activity.

What I discovered was the importance of “MEKUGI” the bamboo pins that hold Japanese blades together.  I also came to the conclusion that Chinese construction seems to have been significantly different – and less refined – than Japanese techniques.

 The tang of the Dao blade was rather loosely set in an open groove in the short section of pole still present. It looks like the pole had been sawed off just beyond the end of the tang. In addition to 4 forged iron rings, the tang was held in place by two (2) iron pins. Based on experience with Japanese polearms, I assumed that these would be comparable to the bamboo pins used in Japan and that they would be removable. In fact, I discovered that the iron pins were essentially fixed. They seemed to have become solidly “rusted” on  to the Dao tang. Even heavy (but careful) pounding would not loosen them. Having committed to the project, I decided to cut the iron pin with a thin blade Dremel tool.

The take away message may be that bamboo mekugi allowed Japanese blades to be removable, and therefore survivable. Are they, in fact, the real secret behind Japanese blades?

Peter

[ChrisW]

I think it is the fact that essentially everything on nihonto is replaceable and interchangeable (with modification) which greatly extends the life of a Japanese blade. I think this is their secret to longevity (that and a culture that reveres and cares for said blades).

[kissakai]

I see the tsuba has a rectangular slot and was was discussed on a previous post so it all adds to our knowledge

 

[Peter Bleed]

Comments by Grev and Chris invite consideration of the guard on this Chinese weapons. As Grev points out, the guard has a rather large, rectangular slot - what WE would call a nakago-ana, but who knows what it was called in China. Interestingly, this guard shows a number of large, coarse forging flaws. Evidence of laminations are to be seen on Japanese katchuchi/tosho tsuba, but these seem - ahhh - remarkable!.

Peter

[ChrisW]

Honestly, it looks like if this were to receive a solid strike, as a tsuba could conceivably receive, then it may have very well shattered. Those are remarkably noticeable forging flaws.

[Bazza]

With those cracks the tsuba looks more like a casting to me.

 

BaZZa.

[Peter Bleed]

Good eye, Bazz, but the flaws do NOT cut straight across the plate. They show up on the opposite face but are well-below where they start out. I think they are just crappy "lamination". If I ever swing another trip to Aus, I'll bring this guard along to show you! (But that will require you to come out west of Hoppers Crossing).

Peter

[Bazza]

> (But that will require you to come out west of Hoppers Crossing)

 

TOMORROW??????

BaZZa

[Rivkin]

There've been comments on mekugi materials throughout time and space. Wood is obviously the cheapest, but outside of Japan they were considered too fragile, and copper or iron was used instead. There is even a Roman source on this.

The number of ana is typically one or two. Indeed, loose mekugi was seen as something extremely dangerous and thus many moved to extremely tight (like copper bolt hammered into iron ana) or even non-removable placement.

[WillFalstaff]

One consideration is that this polearm was arsenal grade, meaning there wasn’t a need to make it last generations.

 

For example, some Viking blades were passed on from generation to generation, with the hilt being replaced when a new owner received the sword and wanted his own type, or the old hilt fittings were too corroded and had to be replaced. The tang was most likely hot or cold peened and it would have taken a master swordsmith to make the modification, but there are examples of reworked hilt constructions in museums.

 

Same could be said about some Chinese swords that were better made than your average “G.I.” issue stabbie-stabs, and modifications were considered for the blade down the road. Also, China had a lot more natural resources than Japan, so they could “afford” to make weapons that were sitting on a rack for a long time before being used. 

 

[Bugyotsuji]

Ritual purity and cleanliness may have played a part culturally. Dismantling and cleaning. Imagine being unable to remove a gory hilt that has run with blood.

 

Once removable was the preferred way to go, then a search for mekugi as strong as metal would quickly turn up susudake (smoked bamboo) as a candidate. Ordinary bamboo could also be fashioned to substitute in a field situation if your portable supply is lost.

[Wolfmanreid]

9 hours ago, WillFalstaff said:

One consideration is that this polearm was arsenal grade, meaning there wasn’t a need to make it last generations.

 

For example, some Viking blades were passed on from generation to generation, with the hilt being replaced when a new owner received the sword and wanted his own type, or the old hilt fittings were too corroded and had to be replaced. The tang was most likely hot or cold peened and it would have taken a master swordsmith to make the modification, but there are examples of reworked hilt constructions in museums.

 

Same could be said about some Chinese swords that were better made than your average “G.I.” issue stabbie-stabs, and modifications were considered for the blade down the road. Also, China had a lot more natural resources than Japan, so they could “afford” to make weapons that were sitting on a rack for a long time before being used. 

 

 

Some Chinese swords were truly extraordinary...  The Portuguese Military Museum in Lisbon has a couple Yuan/Ming dynasty swords that are spectacular.  The fittings are as good or better than some of the best Japanese work I've seen.  I can't speak the metallurgy of the blades but certainly the Chinese were no slouches in their technological and metallurgical proficiency going back millennia.  

Interesting the seminal Chinese military work Wubei Zhi from the 16th/17th century devotes considerable space to discussing the quality and use of imported Japanese swords, which were apparently quite well regarded in China at the time.  

 

https://en.wikipedia.org/wiki/Wubei_Zhi

[Franco D]

Food for thought,

 

Nihonto through the early times were battle tested. That is the sword smiths would have received direct feedback as to how the sword performed or failed under stress. Perhaps a wooden mekugi was the result of this. When one watches the high speed film of a modern sword being tested on a kabuto, what one sees is that the sword undergoes incredible forces, distortions. As such if there wasn't some give somewhere designed into the system to absorb the transfer of energy, almost assuredly the sword itself would fail catastrophically. Both the mekugi and the habaki (the habaki would be the first in line in the transfer of energy) could be by design engineered to fail before the sword. 

[IanB]

To some extent, the material from which mekugi are made is irrelevant. The forces acting on a blade as it strikes are transmitted from the tang to the tsuka because the latter is shaped internally to fit tightly onto the tapers of the former, both in width and thickness. The primary purpose of the habaki is to prevent the tapered tang being driven further into tsuka and splitting it. Its secondary function being to secure the blade in the saya, again because of its tapered shape. These taper fits are exactly the same as the morse taper system used to drive machine tools and drills. The only function served by the mekugi is to stop the tang being jarred out of the taper fit from the forces of a blow, hence smoked bamboo, buffalo horn are perfectly adequate to the task. Just occasionally you will come across an old mekugi that shows an indentation where the side of the mekugi ana has crushed the bamboo - an indication that the tsuka no longer fits the tang properly because of wear or distortion of the cavity in the tsuka.

Ian Bottomley.

[ROKUJURO]

Ian,

that is a perfect description of the function of the handle parts! This small text should be pinned for eternal information! The MEKUGI does not 'hold' the blade! In addition, this text underlines the importance of a new (or intact) wooden TSUKA core and TSUKA-ITO for a sword in use! Swinging a sword with old KOSHIRAE parts (especially dried out TSUKA with possible damage) can be dangerous! 

Peter's impressive GUAN DAO might well have been a simple arsenal weapon, made the fast and cheap way. In times of great armies, many weapons were made just for equipment purposes so that a homogeneous look at the front line would frighten the enemy. The reason for the cracks on the TSUBA might be a result of bad forging (= fire-welding) and probably using surplus or waste material with a carbon steel content. Pure wrought iron would not crack easily unless forged cold. 

[Bazza]

Ian, its worth adding a little emphasis here for those not inculcated into machine shop practice.  The precise function of the taper is to LOCK the 'fitter' into the 'fittee', so to speak.  For example, the purpose of the taper on the rear axle of a car is to 'lock' the axle to the taper of the hub.  Those who have tried to get a hub off with out a puller will know exactly the problem.  Even those using a puller will sometimes have difficulty getting things to come apart.  Similarly, a tsuka made by a highly skilled artisan will 'lock' the tapered nakago of the blade into the tsuka and the tapered habaki then 'locks' the blade into the saya.  Thus, a properly fitted Japanese sword can be held upside down without the mekugi in place and the blade will remain secured in the saya.  The passage of time, of course, gradually weakens this dynamic.

 

BaZZa.

[Franco D]

19 hours ago, IanB said:

 

 

 

 

 

 

 

[Franco D]

On 2/22/2022 at 5:58 AM, IanB said:

The forces acting on a blade as it strikes are transmitted from the tang to the tsuka

 

 

Pardon? The force acting on a blade as it strikes an object begins at the point of impact before traveling down the sword. Which places the habaki first inline as a point of possible resistance as the sword bends and this energy transfers down the sword. High speed film shows that when a sword strikes a kabuto the sword begins to distort backwards in an arc. If the habaki were not to flex the sword could quite possibly fail meeting that resistance. The next point of resistance as the sword arcs backwards would be the seppa - tsuba or the front of the tsuka in the case of a shirasaya. Which means that if there was play between the mounts, or the tsuka in the case of a shirasaya, and the habaki due to not being fitted correctly, the sword could very well fail as it continues to arc backwards and encounters resistance with those surfaces. 

 

 

On 2/22/2022 at 5:58 AM, IanB said:

The primary purpose of the habaki is to prevent the tapered tang being driven further into tsuka and splitting it.

 

Hmm, if that was so, then please explain why there are so many loose fitting habaki in unsplit tsuka? Please explain why it is that we see habaki that have been cut, split, or damaged where it contacts the hamachi in unsplit tsuka? 

 

On 2/22/2022 at 5:58 AM, IanB said:

The only function served by the mekugi is to stop the tang being jarred out of the taper fit from the forces of a blow

 

No mekugi, sword slides forward in saya, broken kissaki. No mekugi, sword goes flying, becomes a projectile with cutting motion.

 

edit: 2/23/22.

Further, so the mekugi is not there to lock in the tsuka on the backside in relation to the habaki locking in the tsuka on the front (sword) side? 

Edited February 23, 2022 by Franco D
rewrite, clarification, further

[Paz]

Another thing to add is the horror stories that some foolish people have done with wallhanger stainless Steel swords. These have rat tails tangs  and swinging one with impact is a high chance of snapping the blade into a helicopter. Modern production blades replicas of katanas usually have two bamboo pegs, and these take a regular beating. I've seen one sword from cheness which had a metal mekugi and the sword was used on all sorts of targets from metals and poles without snapping. 

 

I agree that Japanese swords were seen as more than swords or tools. They had a spiritual aspect to them, and were treated far better than swords from other parts of the world. Which is why we are lucky today to continue a preservation of sword which may look like it was made yesterday. 

[Dave R]

5 hours ago, Paz said:

Modern production blades replicas of katanas usually have two bamboo pegs, and these take a regular beating. I've seen one sword from cheness which had a metal mekugi and the sword was used on all sorts of targets from metals and poles without snapping. 

 

 I suggest this is done for the same reason the Riinji swords have double mekugi... They don't trust the fit of the wood to the metal. It takes skill, time and handwork all of which are costly in a factory situation!

[IanB]

Franco,  You mention swords with loose fitting habaki that have unsplit tsuka. Such a sword is not in a condition to be used to strike anything. A blade that is to be used should have an habaki that fits tightly to the tang and butts against the ha machi and mune machi equally. Many blades have been polished, sometimes more than once, since their existing habaki was made for them and hence no longer fit tightly on the tang as it should. It has been said many times that the habaki is the only fitting that belongs to the blade and not to the koshirae. You are correct in stating that the seppa and tsuba, and in fact the base plate of the fuchi, all play their part when the sword strikes an object, but they are in effect an extension of the rear edge of the habaki preventing the tang being forced further into the hilt. Properly fitted, the blade of a sword with the mekugi removed will still fit tightly in the hilt until jarred loose - hence the need to hold the sword upright and striking the wrist of the hand holding the hilt. Horror stories of blades shooting out of the hilt when swung without a mekugi are not uncommon for the simple reason the blades no longer fit the hilts as they would have done when in use. Incidentally, a blade in shirasaya was never used to strike anything.

Ian Bottomley

[Franco D]

5 hours ago, IanB said:

A blade that is to be used should have an habaki that fits tightly to the tang and butts against the ha machi and mune machi equally.

 

Hello Ian,

 

When properly made the habaki attaches to the sword itself acting much like a spring clip contacting the sword on three surfaces. There will be instances when in fact the tang is markedly wider than the sword itself due to polishing over time. In such cases, if not most, the habaki will be felt scraping the sides of the nakago as it slides onto and passes over the nakago. A properly made habaki will pass over the sides of the nakago (even when wider than the sword) without scraping and yet fit tightly onto the sword, not the nakago. 

 

5 hours ago, IanB said:

You mention swords with loose fitting habaki that have unsplit tsuka.

 

I should have been more direct, sincere apologies. One big reason for loose and damaged habaki is too often the tsuka when placed back onto the nakago is then seated with a firm tap or even a slap from the palm of the hand. The habaki not being "designed" to prevent the nakago from sliding back too far and splitting the tsuka (even though it acts as a stop) is then pushed/jammed too far forward driving the habaki onto the sword causing it to be damaged. Frequently, this results in a loose fitting habaki and/or a cut and split habaki. It can even result in a damaged hamachi. Since the habaki is not designed for this type of abuse during reassembly, very gentle tapping is required, in addition to using the forefinger and thumb of the non tapping hand to serve as a brake by firmly clasping the habaki, until seating takes place. And if one thinks about it, damage can come at both ends. 

 

[ROKUJURO]

15 minutes ago, Franco D said:

.....One big reason for loose and damaged habaki is too often the tsuka when placed back onto the nakago is then seated with a firm tap or even a slap from the palm of the hand. The habaki not being "designed" to prevent the nakago from sliding back too far and splitting the tsuka (even though it acts as a stop) is then pushed/jammed too far forward driving the habaki onto the sword causing it to be damaged. Frequently, this results in a loose fitting habaki and/or a cut and split habaki......

 

Franco,

you can destroy everything with brutal force!

I have indeed seen damaged HABAKI of the kind you describe, but then it was the result of missing SEPPA or TSUBA or wrong handling and not of wrong design, I think.