How did the office of kampaku expand Fujiwara control over adult emperors?

The office of kampaku was created to overcome the primary limitation of the regency, which traditionally ended when an emperor reached his majority. By establishing the position of kampaku—a chief councillor or chancellor—the Fujiwara family secured a role that was more prestigious and powerful than that of a regent.12

This office allowed the Fujiwara to maintain their dominance over adult emperors by serving as the monarch's official spokesman and the primary intermediary between the throne and the government bureaucracy. Because the kampaku functioned as the real center of authority, the Fujiwara could effectively manipulate the reins of government regardless of the emperor's age. This control was further reinforced by the family's policy of extensive intermarriage with the imperial line, ensuring that Fujiwara daughters were empresses and their descendants occupied the throne, thereby cementing their influence through both political office and familial ties.21