Okinawan/Ryukyuan knife?

[Pitt1999]

Today I bring to your attention a possible first to the forum, what I believe to be an Okinawan/Ryukyuan Yamanaji. Supposedly used in a manner similar to the mainland Japanese Nata, as a hatchet or woodsman's knife, while also being used as a general utility knife. I got this on eBay back in August of last year but didn't think it would spark much interest so I neglected to make a thread regarding it. I began to research (looking for photos of similar examples while on my lunch break) and found that knives of this style are still being made to this day in the region. My example was being sold as a WW2 bringback piece. The leather sheath probably isn't original to the knife, as none of the currently made examples have this type of sheath. There is a stamp on one side of the blade that looks either very worn or partially struck. I leave these pictures to you guys for your comments and speculations!

[Pitt1999]

After seeking some help on the Nihonto Message Board Forum, some of the details of this knife have been straightened out. It was confirmed to be an Okinawan knife most likely made on Ishigaki Island. A user on there identified the worn down stamp as the character "Ishi(石)", leading to the idea that my example was made on the aforementioned island. It was also discussed on there that at one point there were around 30 to 40 blacksmiths on Ishigaki that were in operation, but now there is only one person left that makes knives like these on that island. I know of one other smith on the main island of Okinawa in the village of Ginoza that also makes knives of this type.