Tsunagi won't fit in shirasaya -- should it?

[Chojugiga]

Hello, all. I have what is hopefully an easy question. I recently purchased my first nihontō from a shop in Ginza, which came in shirasaya with separate koshirae. I've since mounted the blade in the koshirae, and I assumed that that tsunagi would replace the blade in the shirasaya. However, the tsunagi doesn't seem to fit, too large for both the saya and the tsuka, and I don't wish to force it.

 

Is the tsunagi intended to be kept in the shirasaya? As it stands now, I have three loose pieces: shirasaya sheath, shirasaya tsuka, and the tsunagi. In case it's relevant, the sword has been in Southern California for about three weeks, and it's cold and rainy here at the moment.

 

Any advice would be appreciated -- thank you!

[Grey Doffin]

Hi Ni-Hyun Kim,

Best guess is that the blade in shirasaya and koshirae are a marriage; the koshirae was made to fit a different sword and was sold with your sword to make an appealing package. It isn't a good idea to place a polished blade in old koshirae; dirt or worse inside the old saya can damage the polish. The shirasaya is the best protection for the blade; best to keep it there.

Grey

[Chojugiga]

Hi, Grey. Thank you very much for your response!

[DoTanuki yokai]

The blade fits well in the  Koshirae ? 
EDIT: Ofc Franco D is right. 
Alternativ is what Grey said.

[Matsunoki]

Can you show us an image of the blade and the tsunagi aligned  next to one another? Do they look the same…..same dimensions?

[Franco D]

The tsunagi was made to fit and for the koshirae, it is not surprising that it does not align with the shirasaya. None the less it should be an exact replica of the sword.

[Chojugiga]

I really appreciate the replies. I've attached photos of the blade and tsunagi side by side. To my eye, they look quite close, although the tsunagi is a little uneven in places. One photo shows the limit to which the tsunagi fits in the shirasaya.

 

Would a gentle sanding be appropriate if it's sufficiently close?

[Mark S.]

The blade is all that matters and everything else is designed to fit around it.  Shirasaya and koshirae should fit blade.  Tsunagi is a place holder for blade in koshirae and all items associated with it when blade is stored in shirasaya. While technically tsunagi should be a copy of blade and fit in shirasaya, it is not important that it does.  Its only purpose is to fit in koshirae and hold all the mounts. 

[John C]

You can see that the end of the tsunagi has straightened and does not match the curvature of the blade. That is probably what is causing it to bind. 

You can sand the end of the tsunagi down so that it fits, which will change the end shape or you can steam (or boiling water) bend the end back into shape (google how to do this. You will need a jig or form). But as Mark said, it's just there to hold everything in place when the blade is not there so it is up to you. For that matter, make a new one!

John C. 

[Grey Doffin]

You should not sand the tsunagi. Doing so can introduce abrasive grit into the shirasaya and then, if the blade is reintroduced to the shirasaya, the polish will be scratched. A sharp plane is the better tool to use for reshaping the tsunagi.

I doubt that anyone could successfully bend the tsunagi with steam or boiling water (sideways yes, but not front to back); it is too thin to survive the force needed to reshape with steam (which is more proper for bending wood; boiling water not so much). Spoken from 50 years as a furniture maker.

Grey

[Jacques]

If it is only a length problem, the best solution is to cut the tip.

[Matsunoki]

You could also use the blade of a plane as a scraper on the tsunagi if the plane itself is too unwieldy…..or buy a custom scraper…..but as above….don’t sand it. Go with the grain, not against it. 

Cutting the  tip won’t help if the “jam” is at the habaki end….it will just spoil the aesthetics of the tsunagi.

To my eyes it is the depth of the tsunagi blade that looks a bit bigger and the kissaki looks different.

Gentle approach….little at a time.

You can sometimes “feel” where the jam occurs and even hear it….seriously!

[Matsunoki]

…..but as Mark said above….. it’s best to leave the blade in the shirasaya and the tsunagi in the koshirae…..that’s the way it’s safest and it’s the way it’s meant to be.

[Chojugiga]

Thank you all for the very thoughtful input! It feels like it is sticking near the kissaki, so I will try some very gentle planing to see if it will fit.

[Bugyotsuji]

I had a tsunagi made for a koshirae and it was beautifully done, but the thing did not seem to shut all the way. It was a special kind of aikuchi, tight at the best of times, even without the tsunagi, so I thought it was a problem with the fuchi and koikuchi interlock. 

 

I gave it some extra oomph and it closed, but it made an annoying dent in the edge of the kissaki. In despair, I mentioned it to my sword teacher and he looked at me as if I was crazy. "It's just a tsunagi", he said. "File it down."

I must have looked kind of amazed.

"Not sure if I could do that myself..." I muttered, thinking of the proportions.  

"Well, if you have problems then give it to me and I'll sort it for you!"

 

Going back to Gray's first answer, I would agree. I think the shop just quickly chose something by eye that you could easily alter later on.

 

Having said that, I notice that many dealers faced with buying a koshirae and shirasaya 'set' will double check to see that everything fits each other.

 

Nothing to do with the price of fish, but there is a Japanese saying about a marriage that is not working, 反りが合わない "Sori ga awanai", i.e. the sword and sheath do not fit together well. In your case Ni-Hyun, the blade itself fits well into both, so you are (relatively) laughing! 

[WillFalstaff]

It’s a piece of wood meant as a place-holder. Plane it down. Probably an issue with wood swelling. Don’t sweat it. Don’t use sand paper because it could leave abrasive particles that can scratch the metal of the bade. Carve it down using a sharpe edge.