From the age of 19 or 20, Motobu, along with his older brother Chōyū and his friend Kentsū Yabu, began studying under Kōsaku Matsumora. He was taught by Matsumora, especially irikumi, an ancient form of kumite, and Matsumora praised him as being very talented in the martial arts. Yabu was a good friend of Motobu's and they practiced karate together throughout their lives. Motobu famously emphasized Naihanchi kata, but also taught Seisan, Passai, and Shirokuma (White Bear). There is a theory that Shirokuma is Channan because of its resemblance to Pinan. Furthermore, he taught Wanshū and Jitte. Activities in Mainland Japan The boxing match Around 1921, Motobu moved to Osaka, Japan. In November 1922, a friend convinced Motobu to enter a "boxing vs judo" match which was taking place. These matches were popular at the time, and often pitted a visiting foreign boxer against a jujutsu or judo man. According to an account of the fight from a 1925 King magazine article, Motobu is said to have entered into a challenge match with a tall, burly foreign boxer called George. Motobu, on the other hand, recalls that the boxer was John "somebody." Early rounds involved evasion by the smaller man. Motobu recalls the boxer fought very sluggishly. Taking advantage of this, after a few rounds, according to the account, Motobu moved in on the taller, larger boxer and knocked him out with a single hand strike to the head. Motobu was then 52 years old. The King article detailed Motobu's surprising victory, although the illustrations clearly show Funakoshi Gichin as the Okinawan fighter in question. The two were often at odds in their opinions about how karate ought to be taught and used. Motobu-ryū Karate The popularity generated by this unexpected victory propelled both Motobu and karate to a degree of fame that neither had previously known in Japan. In 1923, he opened a karate dojo in Osaka. Among his students at that time were Tatsuo Yamada and Sannosuke Ueshima. In 1926, he published his first book, Okinawa Kenpo Karate-jutsu Kumite-hen (Kumite Edition of Okinawa Kenpō Karate Art). This is the oldest book on kumite, and the 12 kumite drills presented in this book are still passed down in Motobu-ryū today. Around 1927, Motobu moved to Tokyo to establish the Daidōkan dojo and also became the first Shihan of the karate club at Toyo University. Regular students at the dojo