Nakahara Zenzaemon served as a bushō during the Sengoku period. Zenzaemon was a retainer of the Mōri clan – the sengoku daimyō of Aki Province. He was commonly known as Narihisa.
Zenzaemon’s origins are uncertain, but he served the Mōri clan. In 1540, at the Battle of Yoshida-Kōriyama Castle, Zenzaemon killed Amago Hisayuki who was serving as the rear guard for the retreat of the Amago forces.
In 1569, Amago Katsuhisa and Yamanaka Yukimori led an army to resuscitate the Amago clan, invading Izumo Province from a base in Oki Province. At this time, Zenzaemon joined Kodera Mototake to serve as metsuke, or inspectors, under Jinzai Motomichi, a former commander of the Amago who had earlier surrendered and served as the lord of Sueyoshi Castle in Hōki Province. Later, however, Zenzaemon was assassinated by Motomichi who colluded with the army to resuscitate the Amago.