Lifespan: Eiroku 10 (1567) to 4/7 of Kanei 16 (1639)
Rank: bushō, hatamoto
Lord: Oda Hidekatsu → Tokugawa clan
Father: Hoshiai Norikata
Mother: Daughter of Kitabatake Tomonori
Wife: Adopted daughter of Iinō Hisakiyo (daughter of Iinō Shigemune)
Children: Tomohira, Tomomichi, Akiyasu, 専来, Tomotaka, daughters (three)
Hoshiai Tomohira served as a bushō during the Azuchi-Momoyama period and hatamoto during the early Edo period. Tomohira was the fourth head of the Hoshiai clan. The Hoshiai were members of the Kitabatake clan – the daimyō family of Ise Province.
In 1567, Tomohira was born as the son of Hoshiai Norikata, a retainer of the Kitabatake family – the sengoku daimyō of Ise.
After the death of his uncle, Hoshiai Norifusa, Tomohira was raised by his grandfather, Hoshiai Tomokazu, who served as a state councilor for Kitabatake Harutomo. At the time, Tomohira was only one-year old, so his father, Norikata, was serving as a gundai, or proxy for his lord to command forces in battle. In 1572, after Tomokazu died, Norikata succeeded him and moved to Ōkawachi Castle. In 1576, after Kitabatake Tomonori was assassinated by Kitabatake Nobu (later Oda Nobukatsu) in an attack known as the Mise Incident, Tomohira was confined to Yoshino in Yamato Province.
Thereafter, he moved to Owari Province and served Nobukatsu’s eldest son, Oda Hidekatsu. In 1595, upon orders from Toyotomi Hideyoshi, Tomohira became the chief retainer to Hidekatsu and was presented with a precious sword produced by a manufacturer named Aoe in Bitchū Province during the late Heian and Nanbokuchō periods. Tomohira was then sent on temporary assignment to Ōsaka. As a messenger to Fushimi, he received a fief of 300 koku in Kawachi Province. Hidekatsu assigned to Tomohira as his territory the neighborhoods of Ushihara, Ajimi, and Hanakuro.
In 1600, Tokugawa Ieyasu raised an army to subjugate Uesugi Kagekatsu in the Conquest of Aizu. During their march, while this army camped in Oyama in Shimotsuke Province, Tomohira was dispatched along with Murase Shigeharu for the purpose of informing Ieyasu that Oda Nobukatsu and his son, Hidekatsu, had joined the Eastern Army (led by Ieyasu). However, when Tomohira arrived near Odawara, he learned that Ishida Mitsunari had rebelled in the Siege of Fushimi Castle. This news caused Ieyasu to hold a council with his senior commanders to decide whether to continue the march toward Aizu or to return to Ōsaka to confront Mitsunari, an event known as the Oyama Deliberation.
Meanwhile, the two messengers conferred in the town of Sakawa, deciding for Shigeharu to continue as planned to meet Ieyasu to notify him of the original message while Tomohira headed toward the environs of Kyōto to engage in military operations under the direction of Nobukatsu. En route, upon arriving at Kakegawa Castle in the Sano District of Tōtōmi Province, Yamauchi Kazutoyo (the lord of the castle) prohibited travelers from passing-through his territory. Tomohira relied upon an acquaintance with the surname of Iwada to explain the situation to Kazutoyo, whereupon he consented and sent Tomohira along with an army of his retainers. Tomohira rushed back to Nobukatsu along with 2,000 troops. Nobukatsu noted to Tomohira that many retainers were colluding with Ishida Mitsunari, and while he was seeking to ally with Ieyasu, he ignored them waiting for Tomohira and Shigeharu to return. Tomohira then headed toward Hidekatsu in Echizen. With the addition to forces from Aoki Kazunori, he sought to demonstrate his loyalty to Hidekatsu by eliminating Ōtani Yoshitsugu and promptly departed. At the Kinome Ridge in Echizen, he encountered the Ōtani forces and attempted to defeat them, but was cut-off and failed. He then headed back toward Hidekatsu and converged with the forces led by Maeda Toshinaga. Together with the Maeda army, he felled the Daishōji Castle in Kaga Province defended by Yamaguchi Masahiro.
After the Battle of Sekigahara, the Oda family was removed by Ieyasu from its position. Tomohira accompanied Hidekatsu on battles in various locations, until the death of Hidekatsu in 1610. Thereafter, Tomohira was recognized for his contributions during the Battle of Sekigahara and, in 1613, was granted a fief of 1,500 koku in Oda in Hitachi Province. Okada Toshiharu, however, raised an issue with this award, noting to Honda Masanobu that, when Tomohira was a retainer of Nobukatsu, he held several times the territory of Murase Shigeharu, and while his loyalty to his lord was the same as Shigeharu, Shigeharu had a fief of 3,000 koku, but Tomohira’s fief was only 1,500 koku. Masanobu gave a verbal promise, but then Ieyasu and Masanobu died in succession so Tomohira did not receive an increase to his fief. Tomohira participated in the Siege of Ōsaka under the command of Andō Shigenobu.
In 1631, he became a member of the personal security forces for the Tokugawa family. In 1632, he became a high-ranking elder and died in 1639 at the age of seventy-three.