Shizua

I'm pretty sure it has to be stated the "type" when it is crafted or looted. Beyond what defines it (as to what metals are heavy/light, what leathers/etc are heavy/light), I have no idea. I think it's like Who's Line where the point doesn't really matter, long as it's within reason.

If a tailor can make it then its light armor
if a blacksmith can make it, then it is heavy armor