Ishii trained judo since a very young age, at a dojo located near his house, and graduated in pedagogy at Waseda University.

After a sixty-day boat trip, Ishii arrived in Brazil and worked in a farm at a Japanese Brazilian community in Presidente Prudente.

Added to Ishii's frustration with the farming life, he started to teach the martial art, eventually opening a dojo in São Paulo.

[1] He won a bronze medal at both the 1972 Summer Olympics in Munich,[2] and the 1971 World Judo Championships.

Ishii is considered the founding father of modern Brazilian Judo and his legacy is directly linked to the prowess of judo being the only sport in which Brazil has collected medals in every Olympic Games since Los Angeles 1984.