In 1927, Dr. Jigoro Kano (founder of Judo,) came to Okinawa to open a new dojo. Mabuni and Chojun Miyagi had the opportunity to demonstrate Karate for him and explain the philosophies and techniques. Kano was inspired and impressed with Karate and deemed it the ideal art for both offensive and defensive tactics. He spoke with Mabuni and Miyagi about the need to spread the art of Karate in Japan. In 1927, Mabuni made several trips to Japan to teach, and by 1929, he moved to Osaka to teach his style of Karate full-time. At the time, Mabuni called his style Hanko-ryu, or Half-hard Style.

Shito-ryu's beginnings in Japan were tough. After Mabuni moved to Osaka in 1929, he worked diligently and tirelessly to promote the art. That same year Mabuni also worked to continue structuring and organizing instruction, and documented the syllabus. He taught for free at police stations and Buddhist temples.

Being that Karate was an Okinawan art, many Japanese had a hard time accepting it. While Mabuni worked to find ways to make Karate more popular, he never changed his style. He would demonstrate tameshiwari (board breaking) to show the power of the new martial art. He began teaching in police departments and Buddhist temples as well.When he registered the style in 1931 with the Dai Nippon Butokukai (the Japanese organization created to preserve, standardize and promote Japanese martial arts,) he officially named it Shito-ryu, in honor of his two primary instructors, Anko Itosu and Kanryo Higaonna. The “shi 糸 ” derived from the first character in Naha-te master Itosu's name (糸洲), and the “to 東” from the first character in Shuri-te master Higaonna's name (東恩納.) It was in that same year he founded the Dai Nippon Karate-do Kai dojo, which was later renamed Nippon Karate-do Kai.

Kenwa Mabuni passed away on May 23, 1959. Mabuni was passionate about the roots, tradition, and history of Karate-do, probably more so than any other master instructor in over a century. Today his style lives on as one of the four recognized major styles of Karate in the world with practitioners across the globe.