The Buzen Kokujin Uprising was an uprising by kokujin, or provincial landowners, in Buzen Province during the Azuchi-Momoyama period.

After the Pacification of Kyūshū (1586 to1587) by Toyotomi Hideyoshi, the northern half of Buzen was governed by Mōri Katsunobu and the southern half by Kuroda Yoshitaka.  Many of the kokujin submitted to the Toyotomi clan and obtained recognition of their rights to their landholdings, but the true state of affairs differed from their expectations.  Namely, while the landowners expected their preexisting rights would be protected, instead, under the command of the Mōri and Kuroda families, landholdings were simply allocated in the form of a retainer’s stipend, whereas the formerly expansive administrative rights held by these landowners were no longer recognized.  This bred a growing sense of discontent among the landowners.  In the tenth month of 1587, the Kii clan, the largest landowners in Buzen, holed-up in Kiidani Castle and declared a revolt against their new lords, triggering a large-scale uprising by kokujin across the province.

The kokujin traditionally operated on an independent basis so were unable to form an organizational and strategic alliance among themselves to oppose the Toyotomi.  Even the Kii clan who served as the ostensible leaders of the ikki forces were not in a position to command or direct all of the participants nor did the clan wield the power to enforce orders with respect to fellow clans.  As a result, the ikki forces were individually crushed and the eventual surrender of the Kii clan brought the uprising to an end.  While the Kii clan was decimated through deceptive tactics, the uprising was suppressed in name and in substance.

Not all of the families who were members of the Kii clan, in addition to those who were members of the Utsunomiya clan, joined in the uprising.  For example, the Nonaka clan based at Nagaiwa Castle in the Shimoge District participated but the Sata clan in the Usa District did not.  Also, families other than members of the Utsunomiya clan were involved.  For example, the Sasaki clan based at Ganjaku Castle in the Tagawa District participated but, early on, the Tokieda clan based at Tokieda Castle in the Usa District submitted to the Kuroda and helped to counter the uprising.