> On a related tangent, apparently modern karate originated in Okinawa
it's well documented actually, before 1900 or so no one in mainland Japan knew anything about what would later be called karate.
Gichin Funakoshi (father of shotokan karate, even though he never called it that himself) moved to mainland Japan in 1922 to popularize it. Before then only a few people in the Japanese navy and the prince/emperor-to-be had seen it while visiting Okinawa.
Yes, there are other styles other than Funakoshi but he is undisputably the one who broke into mainland Japan first