I have it a little backwards...sorry--long time since history lessons. I must have heard it wrong or just misunderstood. The point does still stand..see quote. "These skills were developed into Karate, “the empty handed way”, and used by the Okinawans in defence against the Japanese who had invaded the small island chain. The Japanese had banned all metal utensils, knives, metal farm tools, pots and pans. The Okinawans practised the martial arts in complete secrecy and finally gained freedom from the Japanese." this quote is from https://www.newmarket.com