Well to be honest I think it is somewhere in the middle. There are obvious cultural aspects that are part of anime specifically in those slice of life type shows but when you start getting into fantasy and scifi I think the line is blurred and really doesn’t matter.
To be technical about it most anime is made in Korea. So technically it ain’t anime either IF your definition is that it must be made in Japan. And if you notice recently China is coming in producing its own anime.
