Expanding on previous comments:
What the law (PC12020) *really* says is that you "cannot conceal a readily available stabbing implement". That same section gives an *example* of what constitutes legal open carry (openly suspended from the waist is guaranteed cool) but that should NOT be read as the only possible open-carry method.
It IS being read that way by some cops and DAs. In the case of People vs. Terrence Terry (Richmond Calif. Superior Court, 1998), he had an openly-strapped-on-the-ankle double-edge dagger that they tried to nail him on a felony for...he got off because I wrote to his public defender explaining that just because waist carry was given as an example doesn't mean it's an absolute.
So: A 3" fixed-blade neck knife on a string OPENLY around your neck is cool, but you'd best go understand all of PC12020 and be ready to politely teach it to a cop.
Folders are regulated under PC653k. If it's got a thumbstud/hole/disk/whatever, it's cool. Switchblades of 2" or more are not, neither are Balisongs. There's been one attempted bust over a Lever-lock, I dunno whare that's going. The CUDA hasn't come up as an issue but since the thumbstud is directly connected to the blade it SHOULD be OK.
PC12020 *does* comment on folders. It says that anything cool under PC653k and is FOLDED isn't "readily available" and hence can be concealed.
There are no length limits anywhere in PC653k OR PC12020.
There ARE local ordinances against bigger knives. Berkeley has one, enforcement is pretty serious. So does SF, enforcement is spotty. In all cases, enforcement will go up as your attitude gets poopy #1, and as the knife gets bigger a distant second. Violations are INFRACTIONS.
What it means is, a SIFU might be illegal in the People's Republic of Berkeley but if you conceal it things don't get worse and your odds of a cop seeing it are borderline non-existant. Unless you have to use it god forbid, and then you're STILL not facing serious legal problems just from the carry. I don't carry $300+ fixed-blades in Berkeley, I sometimes do in SF. Your milage may vary.
Last detail: there are fixed blades that can at least theoretically escape the "stabbing implement" part and could therefore be concealed. If the blade is 2" or less, a decent case can be made in that direction although that's UNTESTED. A TRUE Sheepsfoot blade such as the Myerchin A500 can be explained away as a "crash rescue knife" that cannot stab due to the blunt tip, see also
http://www.myerchin.com
ATTITUDE COUNTS. If you can calmly and politely explain what the law REALLY is, they're liable to figure you can do the same thing in front of a Judge or Jury.
My webpage has a link to the Calif. laws and codes looker-upper.
Jim March
Equal Rights for CCW Home Page
http://www.ninehundred.com/~equalccw