Lifespan: Kyōroku 2 (1529) to 6/8 of Tenshō 6 (1578)
Other Names: Tarōshirō
Clan: Sagae clan (descended from Ōe no Chikahiro)
Father: Sagae Hirotane
Mother: Daughter of the Yūrin Temple
Wife: Daughter of Yoshikawa Masatoki, [Consort] Daughter of Shiraiwa Munehiro
Children: Kotohime (wife of Sagae Takamoto)
Sagae Kanehiro served as a bushō during the Sengoku and Azuchi-Momoyama periods. He was the seventeenth head of the Sagae clan and lord of Sagae Castle in the Murayama District of Dewa Province.
In 1529, Kanehiro was born as the son of Sagae Hirotane. In 1546, in the wake of his father’s demise, Kanehiro inherited the headship of the clan. The Mogami and Daihōji moved in the direction of an alliance, but, according to a letter from Tosabayashi Zentō, the negotiations broke down. In 1560, Mogami Yoshimori and Mogami Yoshiaki (father and son) assaulted Sagae Castle, but Kanehiro repelled them. Perhaps owing to this attack, branch families including the Mizonobe, the Shiraiwa, and the Aterazawa sought further autonomy from the Mogami. The following year, Kanehiro’s name appears in records of the Jion Temple in Sagae as an almsgiver. Without obtaining the permission of the Sagae clan, he issued a certificate recognizing the rights to his territory.
Kanehiro wed the daughter of Yoshikawa Masatoki of the Dewa-Yoshikawa clan serving as the main branch of the Sagae-Ōe clan, but he did not have any sons so, in an effort to solidify his governance, he received the daughter of Shiraiwa Munehiro (an illegitimate branch) as a consort. After marrying a member of the Yamanobe clan, his aunt bore a daughter who later became the formal wife of Mogami Yoshisada. After Yoshisada wed the younger sister of Date Tanemune, he died so his influence was limited. The sisters of his wife wed Shiratori Nagahisa (the lord of Yachi Castle) and Kishi Mimasaka-no-kami (the lord of Yatsunuma Castle), forging an alliance with the Dewa-Yoshikawa clan founded upon these familial ties. This is in contrast to the alliance formed by his father, Sagae Hirotane, with illegitimate branches of the Mogami including the Nakano, the Tateoka, and the Yamanobe clans.
Although the covenant between the Mogami and the Daihōji ended in discord, when Ninagawa Chikayo who had fallen into ruin in Kyōto came to Dewa through the assistance of Tosabayashi Zentō, Kanehiro sent him to the Takamatsu clan for protection. As such, he appeared to maintain friendly relations with the Daihōji clan.
In Tenshō 2 (1574), in an event known as the Tenshō Mogami Conflict, Mogami Yoshimori and his backers engaged in battles across the Mogami territory in Dewa against his eldest son, Mogami Yoshiaki, over control of the clan. In this conflict, Kanehiro sided with Yoshiaki in opposition to the Shiraiwa, the Aterazawa, and the Mizonobe clans supporting Yoshimori who was also backed by Date Terumune, a sengoku daimyō and the sixteenth head of the Date clan. In the first month of 1574, the clans supporting Yoshimori, along with Shiratori Nagahisa, the Tendō, the Kurazō, and the Nobezawa clans, attacked Kanehiro at Sagae Castle. Except for the main citadel, the castle was destroyed. As an outcome of this attack, Kanehiro submitted to the Date, but, in the seventh month, Kanehiro again waited upon Yoshiaki. This news upset Date Terumune, who rode himself to Shinjuku in the Yashiro manor and sent a letter to the Nakano, the Takadama, the Kurazō, and the Tendō to request their deployment. Watari Motomune and Rusu Masakage also participated in the midst of an explosive situation. Owing to signs of a settlement between the Date and Mogami, the Date pulled back. In the eighth month, the Date and Mogami clashed at Narage, and, in the ninth month, a reconciliation finally brought an end to the attacks and the Tenshō Mogami Conflict.
Thereafter, Sagae Takamoto, the older brother of Shibahashi Yoritsuna (serving as a provincial consul) who had inherited the Dewa-Yoshikawa clan, wed Kanehiro’s daughter and inherited the Sagae clan.
Kanehiro died on 6/8 of Tenshō 6 (1578).