Hirofumi Goshi Yamaguchi was born in Shinjing, Manchuria on September 28, 1942, as the 3rd son of Kaiso (the Founder) Master Gogen Yamaguchi. In 1951, at the age of eight, he began practicing karate do at Senzoku Dojo in Asakusa. He received the 1st dan in 1957 and the 2nd dan in 1959. In 1962 he became a 3rd dan holder and an Instructor.
He entered Nihon University in 1963, majoring in cinema studies in the Department of Arts. While he was a student, he had an opportunity to teach karate-do at an American branch dojo for a year. After he came back to Japan, he taught in various Goju-ryu dojo. He graduated from University in 1969, when he became a full time Shihan in the head dojo with a view to promote and develop Goju-ryu Karate do. He has visited and taught in more than 40 countries in the world thus far as an authorized instructor of Goju kai, All Japan Karate do Federation, Tokyo karate Federation, and as an international referee.
After Gogen Yamaguchi died, 20th May 1989, Goshi Yamaguchi was appointed to president of All Japan Karate-do Goju-kai Association, International Karate-do Goju-kai Association, and Saiko-Shihan (Grand Master) for these two associations.