Itosu was born in the Yamagawa Village, Shuri, and became a
Sokon "Bushi" Matsumura at a very early age. As an educated
man well-versed in Chinese classics, Japanese classics and calligraphy,
he held the position of Secretary for the Administrative Office
of the Ryukyu kingdom under the last Ryukyuan king, Sho Tai,
until the monarchy was dissolved in 1879.
In April 1901, Itosu introduced karate to the physical training
curriculum at the Shuri Jingo Elementary School. Four years
later he became the karate teacher at the Prefectural Dai Ichi
College and the Prefectural Teacher's Training College. In 1908
he wrote a letter (now referred to as the "Ten Articles of Karate")
to the Prefectural Education Department which led to the introduction
of karate to all Okinawan schools.
Anko Itosu is credited for simplifying Matsumura's katas. Itosu
split the Pinan kata into Pinan Shodan, Pinan Nidan and Pinan
Sandan. He is also credited with creating Pinan Yondan and Pinan
Godan. He also took the Naihanchi kata and broke it into three
katas: Naihanchi Shodan, Naihanchi Nidan and Naihanchi Sandan.