Two things I find puzzling are the tapered notches at the base of the scales where they meet the bolster. The other feature is the feathery looking engraving on each side of the blade where the filing on the spine ends. First thing that came to my mind was the marks you find on a dipstick to tell you the level of the oil in your car.
In this case when the blade reaches this mark your opponent is dead. (jk)
