Horcrux

Hello, I was wondering if any of you would be kind enough to simply shed some light on my sword. The story my father always told me and still defends to this day is that his great uncle served in WW2 and was lost in Japanese forests for 6 months with nothing but the sword. I was just looking for help Identifying who would have carried this sword as it looks much simpler than the elbaborately decorated swords I've seen here. I believe the Menuki to be a dragon but its not clear and I don't want to ruin the braiding to find out. I would also like to ID the maker's mark on the tang and know anything about the materials it is made from please. I don't plan on ever selling it as its been ij my family for a long time and I intend to keep it as an heirloom. Side note: neither my father or I am responsible for the black tape on the sheath! I believe generations before us put that on, as the condition of the sheath is rather poor.