Rank: bushō and head of the Bessho clan
Title: Senior Assistant Minister of the Treasury
Clan: Bessho – served the Oda
Father: Bessho Norisada
Children: Yasuharu, Yoshichika, Shigemune, wife of Ōgo Sadanori
Bessho Nariharu served as a bushō and head of the Bessho clan of Harima Province. Nariharu was either the son of Bessho Norisada (who died early) or Bessho Noriharu (who may have been his grandfather).
The Bessho clan were associated with the Akamatsu clan from the time of Akamatsu Mochinori in the late fourteenth century. Bessho Noriharu was a senior retainer of Akamatsu Masanori, a sengoku daimyō and the ninth lineal head of the Akamatsu clan. Noriharu was chosen to become the shugodai, or deputy governor, of eastern Harima. Until that time, the Bessho had been rivals of the Yorifuji, a wealthy family from Harima with influence in the Akamatsu clan.
At the time that Nariharu became head of the clan, the Bessho were under the governance of the Akamatsu and occupied Miki Castle. As the Akamatsu waned in power, Nariharu garnered control of three districts in eastern Harima, becoming independent and attaining the status of a sengoku daimyō. This illustrated the phenomenon of gekokujō by which former retainers usurped the power of their provincial lords during the Sengoku period.
Nariharu proved a capable leader, repelling successive attacks from the Miyoshi and Amago clans and expanding his domain to encompass a total of eight districts (Minō, Akashi, Kako, Innami, Kasai, Katō, Taka, and Jintō) in Harima. The Bessho clan witnessed its peak years of prosperity under Nariharu.
Meanwhile, the Akamatsu were under further challenge by the Uragami, shugodai of Harima. Uragami Muramune separated from the Akamatsu and joined with Hosokawa Takakuni in a bid to take control of eastern Harima. Noriharu combined forces with Yanagimoto Kataharu to resist their advances, battling against the Yorifuji who had aligned with the Uragami clan. Kataharu died in the conflict and the Bessho lost Miki Castle to the Uragami, only to recover the castle after a battle known as the Daimotsu kuzure, or the Collapse in Daimotsu, that led to the demise of Takakuni and Muramune. Thereafter, Nariharu repelled an attack by Amago Haruhisa, but was subjugated by Arima Shigenori and Miyoshi Nagayoshi, and entered into a settlement.
In 1556, Nariharu assigned his role as head of the clan to his eldest son, Bessho Yasuharu, later dying in 1563.