Sadachika raised young Yoshimasa ASHIKAGA, the future 8th shogun, and through mediation by Mochikuni HATAKEYAMA, then kanrei (top official post in the Muromachi bakufu), formed a spurious father-son relation with Yoshimasa.
8代将軍足利義政の幼少の頃から養育し、1443年には管領の畠山持国の仲介で義政との擬似父子関係を取り結んだ。