I recently acquired this arisaka bayonet with a rifle that I bought. This bayonet is made by the nagoya company under the Hikari Seiki subcontractor. It was often considered a "Mystery mark" and known as the Nagoya hourglass, but now it is known that it was the Hikari Seiki. It is estimated that there was 450,000 units made. I am hoping that someone can help translate the kanji on the back of the leather hanger. I would love to know if its a name or company, possibly give it some researchable history.