“Shirasaya” is a word which people who have interest in Japanese sword might have heard of before.
Now, let me tell you what the “Shirasaya” really is and what are the functions of it.
Shirasaya is essentially a sheath (Saya) made of plain wood (Shiraki).
This kind of sheath appeared in Japanese history in the last half of Edo period,
and it was used for the long storage of sword.
As it is said “plain”, Shiraki is having no courting, which made it moderately sensitive
to the moisture and even reserves it.
Thus Shiraki has a function as “nightwear (Nemaki)” for Japanese swords as it prevents
swords get rusted.
It is true that some maintenance is necessary for swords even while they are in Shiraki,
but still it can be done without damaging sensitive parts of swords including sheath
and hand-guards which is covered with Shiraki.
- Structure of Shiraki
The structure of Shiraki is really simple: it only has “Mekugi” as a part of it.
Also, Japanese sticky rice is used to glue Saya itself, which is useful when you failed to do
maintenance of sword and it get rusted, as you can break Saya easily and take sword out of Saya.