Others have asserted that he was a member of the Genyosha (the "Dark Ocean Society'), a previous organization founded by Toyama Mitsuru.
However, the membership roles of both of these organizations are meticulously documented, and Yoshida's name does not show up in the registry of either the Genyosha or the Kokuryukai.
While by all accounts a prolific martial artist and teacher, there is little surviving documentation of Yoshida's life that has been translated into English.
Because he was known to have lived an extremely ascetic lifestyle, and possibly as a result of his political activities and connections, most information on Yoshida today has been passed down through oral transmission by primary sources.
At a young age, Yoshida apprenticed himself to Takeda Sōkaku, head of the Daitō-ryū Aiki-jūjutsu school, which would soon become popular throughout Japan as part of the public revitalization of the martial arts.