What Exactly Do I Have Here???

So I’ve had a handful of knives that I grabbed when my grandfather passed away 15-16 years ago and for the most part the majority of them have been in a box that I’ve kept stored in the basement. I kept a couple with my daily carries and in my collection that I pull out and mess with occasionally like his Uncle Henry LB7 and an old Marbles fixed blade.

But I recently moved and started going thru those bins and boxes in the basement and came across this knife in his old box. Not sure if it’ll hold any weight but my grandfather did fight in WWII and would often tell me stories about his time in the pacific theater. The only reason I bring it up is because I remember when I was a kid this knife and another one like it he kept stored out in his shop in the same drawer that he kept all his old military ribbons and medals. So I guess I’ve always assumed he got this from his time in the military.

I cannot figure out what it is tho. I looked it up and down and didn’t find any markings initially. It wasn’t until I started taking pictures to make this post that I found the remnants of lettering on the guard. I’m hoping maybe someone out there could enlighten me as to what the knife is exactly. Who manufactured it, when it was made, what it was made for. I’ve already started trying to get it cleaned up I know it doesn’t look like it but you should have seen it before I spent 3 hours polishing it up and getting all the grime off of it.

Any help at all will be greatly appreciated and I look forward to hopefully figuring out what I’ve got here.