http://knife-expert.com/ca.txt
KNIFE LAWS of the 50 STATES - Introduction and LINKS
The knife knuts tend to keep up to date on these things as much as the gun nuts do.
The "dirk or dagger" part is interesting:
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12020. (a) Any person in this state who does any of the following
is punishable by imprisonment in a county jail not exceeding one year
or in the state prison:
.
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.
(4) Carries concealed upon his or her person any dirk or dagger.
see (32)(e)(24) below, for definitions.
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.
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(32)(e)(24) As used in this section, a "dirk" or "dagger" means a knife
or other instrument with or without a handguard that is capable of
ready use as a stabbing weapon that may inflict great bodily injury
or death. A nonlocking folding knife, a folding knife that is not
prohibited by Section 653k, or a pocketknife is capable of ready use
as a stabbing weapon that may inflict great bodily injury or death
only if the blade of the knife is exposed and locked into position.
(32)e)(24)(d) Knives carried in sheaths which are worn openly suspended from
the waist of the wearer are not concealed within the meaning of this
section.
So, fixed blades under 4 inches, if EXPOSED are legal. If you carry something capable of stabbing someone concealed, you can be arrested (pen, screwdriver, open folder knife, fixed blade, whatever).