His role as a ninja is roughly based on Yamazaki Susumu, but is never really exercised besides one unsuccessful attempt to spy on Gintoki. Despite having a rivalry with Shinpachi, they most often see eye-to-eye out of their respective groups.
Despite his lack of screen time, he came in 4th in the Gintama character popularity poll. But even with his popularity, Sorachi has clearly stated that he will never be on a cover of a Gintama volume.
Yamazaki's birthday is February 6. He is 169 cm, and he weighs 58 kg. His age has not yet been revealed.
His name is based on the historical Yamazaki Susumu.