Bungo Province was under the control of the
Ōtomo clan from the
Kamakura period to the
Sengoku period. Under the tenure of the
Kirishitan warlord
Ōtomo Sōrin, the Ōtomo clan was defeated by the
Shimazu clan from 1586, and were confined to Nyūjima Castle (the predecessor of Usuki Castle). The Ōtomo were saved by
Toyotomi Hideyoshi's 1586-1587
Kyūshū campaign and were allowed to reclaim Bungo province as their territory. However,
Ōtomo Yoshimune (Sōrin's son) behaved in a cowardly manner during the
Japanese invasions of Korea (1592–1598) which so angered Hideyoshi that he was deprived of his fief and banished. Bungo was divided into small fiefs, of which the 65,000
koku holding at Usuki was the largest. This was awarded to Ōta Kazuyoshi, who had a falling out with
Ishida Mitsunari resulting in his being sidelined during the 1600
Battle of Sekigahara. He later died a monk in Kyoto. On the other hand, a general in the Western Army, Inaba Sadamichi, defected to
Tokugawa Ieyasu's Eastern Army and achieved great military exploits at the Battle of Sekigahara, for which he was awarded 40,000
koku in
Mino Province and 50,000
koku at Usuki in Bingo. Throughout the
Edo period, the
Inaba clan continued to rule Usuki for 15 generations. The Inaba clan were classified as
tozama daimyō as they became vassals of the Tokugawa after the Battle of Sekigahara. There was another branch of the Inaba who were
fudai daimyō.
Hayashi Masanari married Inaba Shigemichi's daughter, taking the "Inaba" surname. He later married
Lady Kasuga, the
wet nurse to
Shogun Tokugawa Iemitsu. In Usuki, the 5th
daimyō, Inaba Kagemichi, developed the
jōkamachi of Usuki and the domain's administration. From the middle of the Edo period onward, the domain's finances became tight, and in 1830, the 12th
daimyō, Inaba Terumichi, had debts exceeding 300,000
ryō. For this reason, in 1831, his retired father, Inaba Hiromichi, who had retained political power behind-the-scenes, carried out somewhat rough reforms such as thorough fiscal austerity and new rice field development, as well as the abandonment of old debts and negotiations for grace periods for repayments. As a result, the domain's finances improved considerably. In addition, all of the
daimyō from the 11th
daimyō, Takamichi onwards, either died young or had no heirs, so the domain was constantly on the edge of
attainder as many succession notifications to the shogunate were by posthumous adoptions. In 1844, the domain supplemented its military by organizing a
paramilitary force centered on farmers with rifles who had experience as hunters. In the
Bakumatsu period. the domain maintained neutrality, but in June 1869 Inaba Hisamichi was the first of the Bungo
daimyō to return his domain registry to the
Meiji government, and was appointed domainal governor. In 1871, due to the
abolition of the han system, the domain became Usuki Prefecture, and was later incorporated into Ōita Prefecture. The Inaba clan was elevated to the
kazoku peerage with the title of viscount in 1884. ==Holdings at the end of the Edo period==