Karate is a form of martial arts that was developed in what is now Okinawa, Japan. The Ryukyu Islands of Okinawa were home to the Ryukyu Kingdom, where karate was developed. After Japan annexed the islands in the late 19th century, the martial art form was brought to the Japanese mainland in the early 20th century and adopted into Japanese culture. Karate is a combination of indigenous fighting methods and the Chinese fighting style of kenpo. During the 1920s and 1930s the Japanese fully embraced karate with several clubs opening at universities and the military adopting the art form as a training tool. The martial art form of karate focuses on punching, kicking, and knee and elbow strikes. Some forms of karate even teach grappling, throws, and vital point strikes. Karate can be practiced in four different ways, as either an art, sport, combat sport, or self defense. Karate initially focused on self development while modern Japanese karate stresses psychological development of one's "attitude", including perseverance, fearlessness, virtue, and leadership skills. Sport and combat sport karate emphasizes the use of the art for competition and exercise. Anyone wishing to learn karate will go through three stages of training, basics and fundamentals, forms, and sparring. Karate has come a long way since its development by the Ryukyuans in the 14th century. Karate's entrance onto the world stage was due in large part to Japan's militarism in the middle 20th century. As Japan stretched its borders into Korea, China, and the Pacific during the 1930s and 1940s, its troops brought Japanese culture, including karate, to new shores. After their defeat in World War II, Okinawa became a vital base for American forces and karate became popular among the service members stationed there. Karate spread so far and fast that the term karate began to be used as a general term to refer to any striking-based Oriental martial art form.