It might not mean anything at all, it's not an authentic Japanese katana. It's from Greece. Where it was fabricated, I don't know. The inscription is on the blade, near the handle.
They look like apostrophes and are painted in, so I don't think they're pitting of the metal.
I'm afraid I don't have any pictures, nor a digital camera. That's why I tried to draw the inscription. Sorry.
Oh, NANGI, konnichiwa, I don't know what the other Japanese words mean.