Yes, I have experience with both. Back during the 1940's, the Japanese were trying to organize their karate training sessions they had been enjoying before all of their karate clubs were bombed out of existence and their karate players were conscripted or joined the army. As the men who survived the war crawled out of shelters or returned home to Japan, they found that the Occupational Authority under McArthur did not think very much of their desire to practice military arts - especially considering what had been required to topple Japan's militaristic society and military controlled government. Several of the karate style leaders of the time got together and talked about founding a Japan Karate Association - a non profit corporation which would act as a lobbying group for all Japanese karate. They did this by copying Judo - which was gaining acceptance by the Occupational Authority and starting to be practiced again. The JKA was a loosely organized group - a sort of Trilateral Commission. Once karate was accepted again by McArthur's folks, which was accomplished largely by holding repeated meetings with them and explaining that karate, like Judo, was not a "military art" for the Japanese, but rather a self-help program like the Boy Scouts except with fighting. This obvious lie was overlooked when the Japanese offered to teach their fighting art to the American military, and so karate practices were restored. But it wasn't long after that that the JKA started to turn into a Funakoshi Society, and the guys doing Funakoshi's karate started to call all of the shots. Quickly the Shito, Goju, and other groups bailed out and gave the JKA the finger. The JKA itself started to schism in the 1950's, when the clubs based at colleges run by liberal college professors at liberal arts schools started to have clashes with the instructors of the clubs based at business schools. The business schools had previously been teaching Japanese soldiers how to manage colonial holdings in conquered lands, and so were much more militaristic. They also viewed karate as something that should be organized like the NFL or Major League Baseball - with the JKA serving as the giant profit corporation that oversaw all activities. The college professors all joined each other and bailed out, leaving the business schools and the world's first for-profit dojo behind in the JKA. Those university clubs founded what was known as the University League and eventually joined what was called the Shoto-Kai (Funakoshi Society). The JKA kept going on its own. The first guy to arrive in the US from Japan, Ohshima, to teach karate set up shop in LA in 1955 and ran a club there without any ties back to Japan. He'd seen enough politics and decided that he would keep his club independent. One has to wonder what he was thinking then in 1959 when he invited the very militaristic business school instructor from the JKA Nishiyama to come teach his club for a few years while he traveled the world starting other clubs. Nishiyama immediately tied the club back to Japan's JKA and started changing the practice methods. Ohshima came back to his club and was angry with what had happened. The club split into two parts. Ohshima then founded SKA - Shotokan Karate of America - to differentiate his club and any affiliates from the JKA. I believe this was in reaction to Nishiyama using the JKA brand to market his karate so heavily. Today there are JKA and SKA styles of SHotokan in the US (and maybe a hundred independent shotokan styles that have been founded by Americans). SKA uses older methods. The SKA is like a time machine back to 1955. The number of kata is fixed at the 15 original kata that they claim were the only ones Funakoshi wanted taught. They follow the book Karate-do Kyohan very closely - with a zeal that makes some people a little uncomfortable. They are pretty famous for "Special Training Sessions" that last hours and hours being required for belt proomotions, and students are not allowed to return if they choose to leave. JKA is more modern, more sportified karate. The JKA's goal was always to become the NFL of karate, and so they teach karate with that in mind - the concept always being to create tournament competitors who are fun to watch. The JKA itself has experienced some unpleasant splits within itself. At an SKA club, expect narrower stances and less emphasis on competitive sparring. In a JKA style club, expect more emphasis on winning matches or kata competitions, more stylized and robotic movements. No matter which you go to, if you ask about the other, expect to receive a sneer. JKA and SKA typically do not mix with each other. BTW, the SKA owns an HQ dojo outside of LA that was built using member donations that is absolutely huge. It looks like some sort of church.