Very interesting!Years ago I had a " Swedish fishing knife" who's sheath had a slit strap which folded over and captured the knob on the pommel.
I knew i had seen the little button on top before, old ammo belt pouches.Very interesting. Many military knives use a version of this ball and slit to retain knives and for strap closures on pouches and the like.
It's a interesting blade profile for what is visible. Can you exhibit the whole blade any history and how/when you obtained it?I knew i had seen the little button on top before, old ammo belt pouches.