O Sensei's bokken

Bokken that is used by O Sensei, somehow caught my attention,

One detail is especially interesting, and I have not seen it on any other bokken,

so I decided to make it as my new project.

About this bokken I do not know much, or have information about who made ​​a bokken that used the O Sensei

So I would ask for help all of you, if you have more information or pictures about this bokken.

 

These are the only two pictures I managed to find so far about this bokken, 

on both is the same bokken,

because I do not know who are the authors of these photos, I hope that they will not have anything against what images published on this blog

The first bokken I will try to reconstruct on the basis of these two pictures, when I have more info, I'll make a new one.