Is this sword legal to carry in California?

It is almost 28 inches long, from tip to the end of the actual blade it is 18 and a half inches. My friend told me as long as its in a sheath and visible and under 30 inches it is legal to carry. I know pulling it out and waving it around will break a penal code or two but is it legal to carry it in the open? It has a leather/mesh sheath and is more of a ninja-esque type of sword.