|Affiliation||Nagare Kendo Dojo|
|Voice Actor|| Hiromu Jin (Getter Robo)|
Joji Yanami (Getter Robo G)
Ryusaku is a very stubborn individual, even more-so than his son; dead-set on whatever he has on his mind including his expectations and his own condition.
Ryusaku is a high ranking expert in kendo able to fend off many attacks with just a shinai.
Ryusaku first appeared to drag Ryoma back home so that he could inherit the family dojo. Hayato and Musashi however would not stand for it after what Ryoma did after the sacrifice of Tatsuhito. Seeing Ryoma and his friends' passion allowed Ryusaku to reconsider and let Ryoma stay at the Saotome Institute. He would later turn up at a kendo tournament which everyone knew was strange given Ryusaku's age.