The Iyayama Uprising was an event led by dogō, or small-scale landowners, opposed to the governance of Awa Province in Shikoku by the Hachisuka clan after an event known as the Allocation of Shikoku by the Toyotomi administration in 1585.

Uprising in the Tenshō era

The name of this event originates from Iyayama, a basin for the Iya and Matsuo rivers in a mountainous region in the Mima District of Awa where the resistance was particularly fierce during the period from Tenshō 13 (1585) to Genna 6 (1620).

Residents in Awa Province, especially from the mountainous regions, had deep relations with residents of Tosa Province over the generations and, from early on, came under the governance of Chōsokabe Motochika, a sengoku daimyō and the twenty-first head of the Chōsokabe clan.  Owing to the Conquest of Shikoku by Toyotomi Hideyoshi, Motochika capitulated to the Toyotomi administration.  After Awa Province was granted to Hachisuka Iemasa, a senior retainer of the Toyotomi clan, he aimed to strictly enforce the administration policy to separate the roles of soldiers and farmers as well as to conduct land surveys.  Fearing the loss of their preexisting authority, the landowners located in Iyayama in the Mima District, Niudani in the Naka District, and Ōkuriyama in the Myōzai District launched an uprising.

Iemasa and his senior retainers deployed to the mountainous regions aiming to militarily suppress the uprising as well as cleave-off a portion of the dogō who were in the moderate faction.  In Iyayama where the resistance was particularly fierce, Iemasa dispatched Kita Rokurō-Saburō and Yasuzaemon (father and son) from the local area to persuade the dogō to align with them.  The uprising finally came to an end in 1590.  Thereafter, the Kita clan were appointed to head the mandokoro, or highest political organ, of Iyayama and administered civil affairs in the local area.

Uprising in the Genna era

From 1590, in a majority of Awa Province, progress was made with respect to the collection of swords tied to the policy to separate the roles of soldiers and farmers in addition to the conduct of land surveys.  In Iyayama, in 1607, through the intermediation of the Kita clan, although the self-reporting of rice yields occurred in Iyayama, owing to resistance from the dogō, there was no further progress.

In the eleventh month of 1617, Hachisuka Iemasa dispatched his representative, Shibuya Yasudayū, to meet with eighteen leaders among the dogō in Iyayama and have them requisition twenty-seven precious swords that were family heirlooms.  Yasudayū, via Kita Yasuzaemon of the mandokoro, gave a promissory note and promised payment.  The real intention, however, was to gather the swords as part of the policy of the Toyotomi administration to remove weapons from the populace rather than to pay for the items.  In 1620, after the leaders of the dogō understood the real intent of the Tokushima domain, they led 700 lower class peasants to make a direct appeal to Iemasa and Yasudayū (who were below Tokushima Castle to visit the local shrines and temples) asserting their impropriety and failure to pay.  This enraged Iemasa who then apprehended the eighteen leaders whereupon six were crucified and five beheaded.  The lives of the other seven were spared but they were stripped of their status. 

Afterwards, the authority of the Kita clan in Iyayama was strengthened to the point of being quasi-governors.  All residents other than the leaders appointed by the Kita clan were deemed to be in the class of peasants subject to severe control and exploitation.  Meanwhile, although the Tokushima domain succeeded in purging the leaders of the dogō and confiscating their swords as a means to separate soldiers from farmers, owing to the peculiar command structure within the domain, their plans to conduct land surveys were frequently thwarted while resistance among the residents of Iyayama toward the Tokushima domain persisted until its dissolution in the Meiji period.