In the early Yoritomo's age, he served as Yuhitsu (amanuensis), bugyonin (a magistrate for political operations and ceremonies of the Imperial Court), cortege and others, wrote the first public administration documents at Mandokoro-kissho-hajime (the ceremony announcing the start of new official works) in the article dated October 6, 1184.
頼朝時代の初期において右筆、公事奉行人、供奉人などを務め、元暦元年（1184年）10月6日条には新造の公文所の吉書始（始業式のようなもの）で吉書（最初の行政文書）を書く。