Kampaku refers to the position of a regent in the imperial court of Japan, particularly during the Heian period, where the title was held by a member of the Fujiwara clan. This role allowed the kampaku to exercise significant political power on behalf of the emperor, often acting as the de facto ruler while the emperor remained a figurehead. The rise of the kampaku was closely linked to the increased influence of the Fujiwara clan, which strategically married their daughters into the imperial family to solidify their control over the imperial line.