A striking visual piece.
In a manga called "Attack on Titan" a similar yet substantially different device is used: a rectangular blade holder. (The characters use sword handles with replaceable blades; if a blade gets broken, they throw it away and get another one from the box).
While both devices are substantially different, they do appear to be similar in many ways. So I was wondering - were they inspired by something from an even earlier manga, or possibly a historical japanese device that actually existed?