For centuries the Okinawan people have practiced Karate-do and Kobudo as the means of self-defense from invading Samurai armies and also to develop physical and mental strength. At first the Okinawan rulers forbade Karate-do and Kubudo. Their techniques were kept secret and were passed on in families from one generation to the next. After Okinawa was officially incorporated into Japan in the 19th century, new laws unveiled the secrecy. In 1912, Karate-do and Kobudo were introduced to mainland Japan and later spread overseas. At present, 40 million people in 142 countries around the World are practicing Karate-do and Kobudo.The rigorous training cultivates physical power and a keen mind. Karate-do and Kobudo can be enjoyed as sports or used as self-defense arts. In the 12th century, Okinawa that is composed of many small islands, was divided into many regions, each with its own ruler that controlled local villages. In 1492, King Sho Hanshi united all regions creating the RyuKyu Kingdom. From the 14th to 16th century the kingdom developed into a major trading center between China, Japan and other neighboring nations. Following the unification achieved under Sho Hachi, his successor Sho shin, in love of peace, prohibited the carrying of weapons (Kobodu) in 1477. Okinawans were prohibited from carrying swords, bows and arrows. After Okinawa was officially incorporated as a prefecture of Japan in 1879, Karate-do and Kobudo had been performed in public. In the Taisho period (1912-1926) Karate-do and Kobudo were introduced to mainland Japan, and the early Showa period (1926-1988) they spread overseas.