# Communities > Bladesmiths, Blacksmiths, Artisans and Professionals > Japanese-Style Sword Makers Cafe >  Queastion from Neil Richmond

## Patrick Hastings

"Horn Koiguchi 
I am working on an aikuchi tanto project. I want to make the koiguchi, horn. The question is how to I attach the horn to the saya so that it is "keyed" to the saya and won't, easily, dislodge from the saya. Thanks.

neil"

I thought this would be a good Queastion For this forum since things are still slow...

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## Keith Larman

I'm a bit confused. Maybe I'm not understanding the question, but it is no different from attaching any koiguchi to a saya... I don't know the correct term for the joint, but there is a 2mm-3mm or so width of wood on all sides of the habaki at the mouth (the wood is compressive so that holds the blade in place with a solid fit). The horn should be carved to fit *exactly* over that to reinforce the mouth. Then its shaped to whatever shape you want. Glue it in place. Voila.

If the carving is clean and accurate, there's good surface contact all on the face and inside of the horn. Hence the glue has a lot to hold onto.

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## Patrick Hastings

> _Originally posted by Keith Larman_ 
> *I'm a bit confused. Maybe I'm not understanding the question, but it is no different from attaching any koiguchi to a saya... I don't know the correct term for the joint, but there is a 2mm-3mm or so width of wood on all sides of the habaki at the mouth (the wood is compressive so that holds the blade in place with a solid fit). The horn should be carved to fit *exactly* over that to reinforce the mouth. Then its shaped to whatever shape you want. Glue it in place. Voila.
> 
> If the carving is clean and accurate, there's good surface contact all on the face and inside of the horn. Hence the glue has a lot to hold onto.*


 Kieth that sounds much too simple and straight forward. At least its tedious and painstaking otherwise it would not sound Japanese at all.. :Smilie:

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## Joseph Renner

Simplicity is brilliance.

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## Keith Larman

FWIW...

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## Keith Larman

If the entire koiguchi was horn, it wouldn't hold the blade very well. With the wood up inside, the sword never touches the horn and the wood acts as a cushion/compression hold on the habaki. If the wood is too thin (or they used a hardwood), it won't compress and it simply won't stay tight very well. The horn is there to reinforce the mouth of the saya. Koiguchi literally means "Carp's Mouth". A wide open mouth. The ring is there to prevent the edge from cutting through, but also because it provides a ring that's less likely to crack and a ring that is solid (no glued halves here) to provide a stronger mouth. Saya can be split if the koiguchi doesn't fit snugly since the wood moves and doesn't have the reinforcement. So it both backs up the glue seam (same reason a kojiri is used on the other end) as well.

It also helps keep the saya from getting dinged up on those areas most likely to get hit. The end and the mouth both. Hard edges and wear and tear from noto and nukitsuke...

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## Ted Tenold

Hi All,

I think the term probably best fitting the term you're looking for (although not in Japanese) is "mortice and tenon".  Keith makes good description.  

Depending on the overall furnishings, the koiguchi can also be made of other materials such as Iron (in the case of Tachis) which is called a Kuchigane (metal mouth).  Some better tachi mount I have seen incorporate both;  a primary installation of horn around the "tenon" of wood at the saya mouth, then the horm itself is also "tenoned" for the Iron ring to fit around.  

Lesser saya I have seen did not have horn at all.  One in particular had no mortice at all, but had lacquer mimicking the horn in color and size.  Underneath the lacquer, silk string had been tied around the saya mouth and inlain into a small groove carved just wide enough to recess it from the surface.  The chipped lacquer revealed the construction.  Another I saw had small width of same' doing the same thing, and lacquered over to conceal it.

On another note, when you see a koiguchi with no wood lining it, suspect a refitted, repaired, or shortened saya.  

Ted Tenold

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## Keith Larman

Thank you! Mortice and tenon... That was bugging the hell out of me last night -- I couldn't remember the proper phrase...  I spent too much time making 2 new seppa yesterday and my brain was fried.

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