Lifespan: Tenbun 15 (1546) to 9/3 of Keichō 8 (1603)
Other Names: Hikoroku, 以鈍
Rank: bushō, daimyō
Title: Assistant Master of the Western Capital Office, Junior Fifth Rank (Lower), Chamberlain
Bakufu: Muromachi → Edo
Domain: lord of Bungo-Usuki
Lord: Saitō Yoshitatsu → Saitō Tatsuoki → Oda Nobunaga → Toyotomi Hideyoshi
Father: Inaba Yoshimichi
Mother: Daughter of Sanjōnishi Saneki
Siblings: Sister (wife of Horiike Han-no-jō), sister (wife of Kunieda Shigemoto), Sadamichi, Masamichi, Nobumasa, Yasu, sister (wife of Marumo Kanetoshi), sister (wife of Yamamura Yoshikatsu)
Wife: [Formal] Daughter of Saitō Dōsan, [Second] Inaba-fujin, [Next Second] Daughter of Maeda Gen’i
Children: Norimichi, daughter (wife of Akaza Yasuke), daughter (wife of Nakabō Hidemasa), Hidekata, Michitaka, Daigaku, Hōunin, daughter (formal wife of Shibata Katsutoyo)
Inaba Sadamichi served as a bushō and daimyō from the Sengoku to early Edo periods. In the Edo period, he was the first lord of the Usuki domain in Bungo Province in northern Kyūshū.
In 1546, Sadamichi was born as the second son of Inaba Yoshimichi (Ittetsu) as the eldest son and designated heir of the family. Initially, Sadamichi, along with his father, Yoshimichi, served the Mino-Saitō clan, but, in 1567, surrendered in the face of an invasion by the army of Oda Nobunaga. Thereafter, Sadamichi and Yoshimichi obeyed Nobunaga and served in assorted battles. In 1579, Yoshimichi transferred headship of the clan to Sadamichi and he became the lord of Sone Castle in Mino Province.
On 4/5 of Tenshō 10 (1582), while guarding Iiyama Castle in Shinano Province, Sadamichi confronted a precarious situation after being surrounded as a result of an uprising instigated by Imokawa Chikamasa, but reinforcements soon arrived and Mori Nagayoshi defeated the Ikki forces in the direction of Naganuma Castle so the siege was lifted and the crisis averted. Nevertheless, perhaps owing to his lack of resourcefulness, Sadamichi was removed from his assignment to guard the castle and summoned to Nobunaga’s main base at Suwa while Hayashi Tametada, a retainer of Nagayoshi, replaced him as the chamberlain of Iiyama Castle. During the coup d’état resulting in the death of Nobunaga known as the Honnō Temple Incident, Sadamichi was in the capital and, after hearing the news of Nobunaga’s demise, quickly fled to his home province.
At the Battle of Shizugatake in the fourth month of 1583, Sadamichi served on behalf of Hashiba Hideyoshi, but, at the time, Mino was under the control of Nobunaga’s third son, Oda Nobutaka, so he wavered as to whether to strike back against the son of his former lord. Then, he transferred headship of the clan to his eldest son, Inaba Norimichi. That same year, Sadamichi followed Hideyoshi and attacked Mine Castle in Ise Province, but on the route home, encountered an uprising by locals and faced the possibility of annihilation. Serving in the rear guard, he scattered the Ikki forces on three occasions, forcing them to retreat. In 1587, Sadamichi and Norimichi deployed for the Conquest of Kyūshū. Norimichi invited the scorn of Hideyoshi so he was ordered to be under house arrest. As a result, Sadamichi resumed his former position as the head of the family. That winter, Sadamichi was invested with the titles of Junior Fifth Rank (Lower) and Chamberlain.
In 1588, Sadamichi moved to Hachiman Castle in the Gujō District of Mino whereupon he embarked in a major renovation of the premises. On 4/14, Sadamichi was among those in attendance when Emperor Goyōzei made a visit to a palace constructed by Hideyoshi in Kyōto known as the jurakutei. Later that year, Sadamichi was conferred with the right to bear the Hashiba surname and Toyotomi title.
In the third month of 1590, Sadamichi led over 1,200 soldiers for the Conquest of Odawara, and, under the command of Oda Nobukatsu, launched an assault on Nirayama Castle in Izu Province. Beginning in 1592, for the Bunroku Campaign, Sadamichi joined other commanders to sail to the Korean Peninsula to fight in numerous battles.
In 1600, at the Battle of Sekigahara, Sadamichi initially affiliated with the Western Army and defended Inuyama Castle in Owari Province. Later, however, he switched sides to the Eastern Army and headed-out to assist Endō Yoshitaka and Kanamori Arishige of the Eastern Army during their assault against Gujō-Hachiman Castle in Mino. This is known as the Siege of Hachiman Castle. Thereafter, he guarded Nagashima Castle in the Kuwana District of Ise Province. After the main Battle of Sekigahara on 9/15 of Keichō 5 (1600), Sadamichi joined Katō Sadayasu to capture Minokuchi-Okayama Castle from Natsuka Masaie of the Western Army. Owing to these contributions, Sadamichi was promoted from his former position in the Mino-Gujō domain with a fief of 40,000 koku to serve as the lord of Usuki Castle and the first lord of the Usuki domain with a fief of 50,060 koku in the Amabe, Ōno, and Oita districts of Bungo Province.
On 9/3 of Keichō 8 (1603), he died at the age of fifty-seven.