What are the 2 strips of wood on the sides of the tsuka for? (Pic in post)

[piryohae3]

This is from a video about Bizen's sword museum. At first glance I thought it was a partial samegawa wrap like on cheaper production swords but upon closer inspection, the narrow strips of wood are on the outside which seems to indicate it is indeed a full same wrap. I thought it'd be optimal to have as much of the ito to have direct contact with the same to prevent slippage due to the bumpy texture.

 

 

 

Since rays aren't native to Japanese waters, who did they trade with to get the skins? I wonder how they came up with the idea to use ray skins on a tsuka in the first place.

[IanB]

It is exactly to prevent the same creating bumps along the edges of the tsuka the tin wood shims are there. Remember there is no paper packing along the edges.

Ian Bottomley

[SteveM]

http://www.ksky.ne.jp/~sumie99/samewrapping.html

 

But I question the comment that says ray skins were imported from south seas. I think rays are also found in Japan (at least, that's what wikipedia tells me), and I find it slightly hard to believe that there would have been sufficient south sea trade in ray skins to meet Japan's needs. 

 

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

 

Edit: I think there must be other threads on this topic. As I recall there is always some disagreement over exactly what type (genus) of rayskin is used.

[Ford Hallam]

It might be informative to read Henri Joly's 'Sword and Same" as it contains the Ko Hi Sei Gi by Hogitaro Inada, a fairly comprehensive Edo period text on same used on swords and saya. I cant recall off hand but I pretty sure it covers the sources of the varieties of ray used.

[Logan09]

My understanding is the wood strips are used to get the final shape of the tsuka(and to true up the Ito to the Fuchi/kashira) and to prevent the nodes from catching on the Ray skin(preventing full stretching of the Ito)