1 px black border pls <3
It looks okay for a first try. The background is pretty bland, and the whole sig is a bit long. Of course it's because of the Masamune, but because of it the background is also longer than usual, and since the background looks a bit boring, it drags the whole thing down a little.
The art looks neat, but not very sharp, thought, that might just be me.
Add a border, make the background more interesting. I think the colors are okay, but a bit more diversity might be nice.
6/10