It is around this time that he is assumed to have met Isami KONDO (who later became the commander of Shinsen-gumi), the 4th Head of Tennen Rishin-ryu, who was on a training trip to Sato Dojo in Hino; on March 29 1859, Toshizo formally became a disciple of Tennen Rishin-ryu.
日野の佐藤道場に出稽古に来ていた天然理心流4代目の近藤勇（後の新選組局長）とはこの頃出会ったと推測され、安政6年（1859）3月29日、天然理心流に正式入門した。