At first, Yoshimoto was running his own business while offering Naikan therapy at his home to those who wanted to be clients, but in 1953, he retired from the business, established Naikan Dojo (later Naikan Kenshujo) in Yamatokoriyama City and devoted himself to teach Naikan therapy.
はじめ吉本は企業経営をしながら自宅で希望者に内観をさせていたが、昭和28年、事業から引退し、大和郡山市に内観道場（のちの内観研修所）を設け内観指導に専念する。