And you can thank...Ronald Reagan? Yep, apparently the law was passed while he was Governor of California, and has never been repealed. It's legal to own them ONLY inside a dojo, nowhere else. Private possession or carrying them is a felony in California.
http://blogs.laweekly.com/arts/2012/11/nunchucks_martial_arts_karate.php
http://blogs.laweekly.com/arts/2012/11/nunchucks_martial_arts_karate.php
Nunchucks Are Banned in California...Except in Martial Arts Schools, Where They're All the Rage
By L.J. Williamson Thu., Nov. 15 2012 at 1:37 PM
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In California, possession of an AR-15 -- the same gun that James Holmes used to shoot up a Batman premiere in Aurora, Colo. -- is legal, provided it was bought and registered prior to 2000. Possession of nunchaku, or nunchucks, however, is a felony -- no matter when they were purchased.
The nunchucks ban was added to the California penal code in 1974, at a moment when the United States was in the kung-fu grip of a martial arts craze. Sparked by the 1973 release of Bruce Lee's Enter The Dragon and spurred by such pop phenomena as the TV series Kung Fu and the song "Kung Fu Fighting," martial arts fever was spiking, along with a faddish interest in martial arts weapons.
Menaced by the trend, Newsweek published a sensational article on nunchucks, called "Killing Sticks." The article's alarm bells prompted lawmakers around the country to contemplate bans, but only New York, Massachusetts, Arizona and California followed through, with then-Gov. Ronald Reagan signing California's bill into law.
In California, desperate martial arts instructors made a successful plea to the state assembly the following year to amend the bill. It now allows possession of nunchucks -- but only on the premises of a martial arts school.