During the Heian period, with the move to the system where the reins of power were concentrated on the zuryo who were hitto-kokushi (the head of the provincial governors) in the Imperial Court's governance of the local regions, the class of rich farmers' attacks against the deprivation by zuryo happened frequently.
平安時代、朝廷の地方支配が筆頭国司である受領に権力を集中する体制に移行すると、受領の収奪に対する富豪百姓層の武装襲撃が頻発するようになった。