Thank you for the clarifications, I must confess that the boldness of the contrast set me off.
Josh is right, of course, there's an inserted edge. I can't really make out a distinct pattern at the back, but without more detailed pictures or direct access to the blade, I can't go beyond just an opinion.
I have also to admit an instinctive distrust of Chinese "antiques", probably exacerbated after I had to certify, some time ago, the authenticity of some allegedly
Shang/
Zhou bronze vessels that ended up being very decent fakes. The problem wasn't really spotting them, but justify it in front of the customer, who thought to have inherited a small (or not so small) fortune...
The world of art/antique fakes is an ugly jungle, and in some areas the Chinese are real masters of this "craft".
Again, thanks for clarifying it.