Master Itosu was born in the city of Shuri.  At the age of 16, he started his karate training with the famous Sokon “Bushi” Matsumura.  He was a very close friend of Matsumura’s uchi deshi, Yasutsune Azato, and he was also a student of Shimpan Gusukuma.

Master Itosu was famous for his technical proficiency, his incredible physical strength, his ability to withstand blows, and his vice-like grip. He was instrumental in introducing karate into the Okinawan public school curriculum in 1901.  To help the teaching process, he developed the Pinan kata using moves based on advanced kata which included Kusanku, Passai, Chinto, and Jion.  Master Itosu is also credited with taking the large Naihanchi form and breaking it into the three well-known modern forms:  Naihanchi Shodan, Naihanchi Nidan, and Naihanchi Sandan.

As an instructor, the creative energy he cultivated in his students is evident by the fact that many of them created their own styles of Okinawan Karate-do after his death.  The wide dissemination of his teachings to the masters of various Okinawan Karate-do styles make it a benchmark for bona fide instructors of Okinawan Karate-do to be able to trace their lineage back to Master Itosu.  The lineage of both Shobayashi Shorin Ryu and Shudokan Karate-do trace back to Master Itosu.