California has pretty liberal knife laws...
but breaking them, while somewhat hard to do, is a serious crime.
IANAL, but here's what I understand from what I've read.
Any size fixed-blade knife may be carried openly. No fixed blade knife may be carried concealed.
Any size folding knife may be carried openly or concealed.
Gravity knives, switchblades, and the like, are illegal. No knife may be possessed that uses a mechanical action to open. Spring-assisted manual folders are not mechanically-operated knives under CA law. This is a greyish area, but that's my understanding.
Local police are notoriously unknowledgeable about knife laws. Nonsense like "any blade longer than the width of your fingers is illegal" has been around for so long that even some cops have been known to believe it. If you're really worried about it, print out and keep handy the relevant sections of the law. They're available online, googling "california knife laws" would be a good start.
FWIW, I routinely carry a 5 1/2" blade, 10" overall fixed blade Anza 705 in a leather belt sheath. It's never been a problem. But then, I don't look or act like someone cops would want to hassle. Even if they did, I'm within the law.
I wouldn't sweat it.
--Shannon