All About Pocket Knives

I found this behemoth today and I'm very curious about it. It's got a lot of bone and steel. It weighs a ton, and its got one of the thickest blades I've ever seen on a folding knife. The finish is pretty rough, but there's no rattles. It has half stops, and snaps hard. Like pretty scary with a blade like that, it's a real finger guillotine. The makers mark is visible, while the knife is in a closed position, near the spine. As found it's sharp enough to slice paper.

At first glance it looks like the Japanese made hobo knives and little Keychain multi tool knives (which I'm a big fan of), but it feels significantly sturdier when you hold it.

Anybody know anything about this knife? I'm stumped, don't even know how to word a proper internet search.

I agree that it appears to be Japanese, both by the style and by what I believe might be Kanji letters (which I cannot read, so I could be wrong). At a guess I would say that it is from the 50's or 60's, and not marked for export.
Hopefully someone comes along with more information!

Interesting blade shape. Looks like a sheepsfoot closed but has a big belly. Nice handles.

Google Lens could not translate.