How much gap in Shirasaya?

[Avidmark]

Wondering how much gap there should be if any at all? I was once told by my Iaido Sensei to keep a small gap to not wear out or split the saya. That is for Iaito and not sure if the same rule applies for shirasaya. When I received this Nihonto from the dealer it was completely shut with zero gap, and was very very difficult to open. The picture below shows how I currently have it. Tight to draw open and requires the two fists together and clench my fists. I’ve seen this in a previous post. Should this be fully closed to make it air tight, or is this sufficient?

Thanks for your advice.

[John C]

Should be flush to keep out dust. Give the wood some time to climatize, it may become easier once it shrinks a little, depending on humidity levels.

 

John C.

[Avidmark]

1 hour ago, John C said:

Should be flush to keep out dust. Give the wood some time to climatize, it may become easier once it shrinks a little, depending on humidity levels.

 

John C.

Thanks for the advice👍🏻

[Matsunoki]

Mark, what you have is actually a very common problem. As humidity and temperature changes the wood (and the habaki) can expand and contract. Whilst what John says above is preferable, it is possible to split the saya exposing the blade to even more problems. If it gets really stuck, as you have found out, it can be hell to draw the blade and that comes with the risk of a mishap or injury if it suddenly releases under undue force.

Id advise not ramming it tight but instead let it sit where it is comfortable but to ensure it is stored in a dust free stable environment with a very thin coat of suitable oil on the blade.

Shira saya made in Japan can often experience these issues when they move overseas!

[Avidmark]

1 hour ago, Matsunoki said:

Mark, what you have is actually a very common problem. As humidity and temperature changes the wood (and the habaki) can expand and contract. Whilst what John says above is preferable, it is possible to split the saya exposing the blade to even more problems. If it gets really stuck, as you have found out, it can be hell to draw the blade and that comes with the risk of a mishap or injury if it suddenly releases under undue force.

Id advise not ramming it tight but instead let it sit where it is comfortable but to ensure it is stored in a dust free stable environment with a very thin coat of suitable oil on the blade.

Shira saya made in Japan can often experience these issues when they move overseas!

Thank you aswell. As stated it came from Japan (a generally humid climate) and its new home is in the geographical center of North America (a generally much less humid climate) in a home with central  heating and central air-conditioning. Although it has had a few weeks to climatize I’ll be sure not to force it closed if it’s telling me it doesn’t like it. Blade came with a large amount of oil which has since been fully cleaned with 99% alcohol and given a very small amount of oil. It also exclusively stays in a shirasaya bag aswell to protect from dust.

[Grey Doffin]

Hi Mark,

Wood of the shirasaya shrinks and expands with changes in humidity; the habaki doesn't. The blade should be inserted far enough that the habaki is comfortable, gripping but not forced. Too far in and the saya can split and/or the foil on a habaki can rip. The gap is not a problem. As for protection from dust, that is why we keep our swords in bags.

Grey

[atm]

Another reason to not force the blade past the point of resistance is that there may be something inside the saya. You may scratch the blade on whatever that is if you continue to push.

[Matsunoki]

3 hours ago, Grey Doffin said:

the habaki doesn'

Grey, of course you are correct for metal habaki. Separate wood or integral wood habaki will however swell and shrink as per the shira saya. Apologies for misleading. 

[2devnul]

On 3/31/2024 at 9:05 AM, Matsunoki said:

Shira saya made in Japan can often experience these issues when they move overseas!

 

I've seen that more then once and not only with Shirasaya (same with Koshirae). As others mentioned, don't put to much force to fully close it. Let it 'fit' and leave it. I think Grey's reply answers the question completely. 

 

PS. My advice, before drawing the sword always 'break the seal'. By that I mean use your thumb to go pass the first stage of sword being 'stuck'. With Koshirae use thumb on Tsuba. With Shirasaya, use both of your thumbs (left+right hand). I apologize if it doesn't make sense (language barrier in order to describe this better). 

[peterm1_nihonto]

In general I like to keep the koiguchi full shut with no gap when the blade is in place. Your Sensei's advice about not splitting the saya is only relevant if the koiguchi is already too tight - not if it fits correctly. If your gap does not rectify itself, after the shirasaya acclimatizes, I would suggest relieving the koiguchi a bit so the habaki does fully engage. This can be done with a small needle file (sets of which are readily available (and usually cheap). Obviously, slowly and carefully is the way to go as taking too much wood off just creates a new problem to solve. 

[2devnul]

@peterm1_nihonto

 

I don't think adjusting Koiguchi on your own is a good idea. Especially if it is a buffalo horn (typical for Koshirae, at least the ones that I own). Like I said, I'm sheeting the sword until it has perfect fit. No chance to leave Saya on its own, also IMHO no chance for any dust to get in. I never struggle in order to fully close the gap. This saves Habaki/Koiguchi/Saya and my nerves when I want to unsheet the sword.  

[Matsunoki]

On 4/6/2024 at 4:14 AM, peterm1_nihonto said:

This can be done with a small needle file

You have no way of knowing exactly where the habaki is “catching”. You could assume it’s at its widest point and be completely wrong……it could be on its leading edge or even on the mune/ha surfaces etc….so where do you start filing?

Do you start using carbon paper etc? Fraught with danger and could very easily make things worse….unless you are an experienced sayashi. Also as temp and humidity changes again you could end up with such a loose fit the blade is insecure. 

[Brian]

You'll find in 6 months it's suddenly loose. Huge difference in fit between Summer and Winter. I have shirasaya that you can barely open at times, and 6 months later it's a perfect fit. When made, it would have been a good fit, so it's likely the weather. Let it sit for a while and acclimatize.

[Grey Doffin]

Wood never stops shrinking and expanding with change in humidity. With time the seasonal change lessens but it doesn't disappear. Grey

[stackinnutts]

On 4/7/2024 at 1:10 PM, Grey Doffin said:

Wood never stops shrinking and expanding with change in humidity. With time the seasonal change lessens but it doesn't disappear. Grey

Exactly; lets not forget we are dealing with an organic material.

[stackinnutts]

Side note discussion... is there a way to distinguish the age of saya by its features? For instance, I notice that in this picture... the little white circular bit around the mekugi; on some others I notice nothing. Is there a distinction of age in this or just build style?

 

 

[2devnul]

Hi,

 

Just style IMHO, sometimes buffalo horns are used (or other material) for Mekugi-Ana. 

You can for sure tell the age of the wood, but that will cost a lot and you need to find a lab which will do this as per commercial order. 

[stackinnutts]

18 minutes ago, 2devnul said:

Hi,

 

Just style IMHO, sometimes buffalo horns are used (or other material) for Mekugi-Ana. 

You can for sure tell the age of the wood, but that will cost a lot and you need to find a lab which will do this as per commercial order. 

Thanks for responding; do you know if there are any resources (online, books) that might explain the differences in styles, periods, and schools associated with such styles??

[Brian]

There aren't any. It's just personal choice when ordering one. No associated styles or schools.

[stackinnutts]

6 hours ago, Brian said:

There aren't any. It's just personal choice when ordering one. No associated styles or schools.

Thanks Brian!