After Yoshimitsu died in 1408, she was not on close terms with Yoshimochi, who succeeded him, and due to his negating the court measures of Yoshimitsu, Yasuko's funeral was not positioned as a mother of an Emperor.
1408年に義満が没した後、後を継いだ義持は実妹の夫であったが疎遠であったらしく、義持による義満の朝廷政策の否定の影響もあって康子の葬儀は国母に準じた儀ではなかった。