Anko "Yasutsune" Itosu (糸洲 安恒) was born in 1831 in Gibo village, Shuri, in the Ryukyu Kingdom, a low-rank Ryūkyūan Pechin, Itosu was small in stature, shy, and introverted as a child. He was raised in a strict home of the keimochi (a family of position), and was educated in the Chinese classics and calligraphy.
Itosu began his Tōde (karate) study under Nagahama Chikudun Pechin.
Itosu served as a secretary to the last king of the Ryukyu Kingdom Shō Tai (尚 泰, 1843-1901), until Japan abolished the Okinawa-based native monarchy in 1879.
In 1901, he was instrumental in getting karate introduced into Okinawa's schools. In 1905, Itosu was a part-time teacher of Tōde at Okinawa's First Junior Prefectural High School. It was here that he developed the systematic method of teaching karate techniques that are still in practice today. He created and introduced the Pinan kata (forms) as learning steps for students, because he felt the older kata were too difficult for schoolchildren to learn. The five Pinan forms were (allegedly) created by drawing from two older forms: kusanku and chiang nan.
According to Chibana Chosin, Itosu may also have expanded on the existing Naihanchi kata to create the third form, which would become Naihanchi Sandan. In 1908, Itosu wrote the influential "Ten Precepts (Tode Jukun) of Karate", reaching beyond Okinawa to Japan. Itosu's style of karate came to be known as Itosu-ryu in recognition of his skill, mastery, and role as teacher to many.
Itosu taught many karate students who went on to be masters themselves, some of those students included Choki Motobu (1870–1944), Kentsu Yabu (1866–1937), Chomo Hanashiro (1869–1945), Gichin Funakoshi (1868–1957), Kanken Toyama (1888–1966), Shinpan Shiroma (Gusukuma) (1890–1954), Kenwa Mabuni (1889–1952), and Chōshin Chibana (1885–1969).
Master Itosu passed away on 11th March 1915 at the age of 84 in Shuri village, Okinawa.
