Lifespan: Tenbun 22 (1553) to 7/3 of Tenshō 6 (1578)
Lord: Oda Nobunaga
Father: Amago Sanehisa
Siblings: Ujihisa, Yoshihisa, Suehisa, Tsunehisa, Katsuhisa, Michihisa
Children: Toyowakamaru, Tsunewakamaru
Amago Katsuhisa was a family member of the Amago clan of Izumo Province. Katsuhisa was the fifth son of Amago Sanehisa. In 1554, when Sanehisa, Amago Kunihisa (Katsuhisa’s uncle), and the shingūtō (an elite group of fighters for the Amago) were purged by Amago Haruhisa, Ogawa Shigetō came to the aid of Katsuhisa. Later, Haruhisa served as his guarantor and Katsuhisa entered the Tōfuku Temple in Kyōto as a monk.
In 1566, continuing attacks by the Mōri led to the elimination of the Amago clan. In 1568, Katsuhisa departed from the temple in a bid to restore the Amago family with support from Yamanaka Yukimori and Amano Takashige. He awaited his opportunity from Oki Province. In 1569, Katsuhisa entered Izumo from Oki and, with the support of former retainers, set-up a base in Shinyama Castle. He aimed to re-take Gassantoda Castle, but the effort failed owing to a fierce defense by Takashige and Mōri Motoaki. In the second month of 1570, Katsuhisa experienced a bitter defeat to the Mōri at the Battle of Fubeyama, fleeing to Kyōto. In 1574, Katsuhisa received support from Yamana Toyokuni to attempt an invasion from Inaba Province, but this also ended in loss.
Thereafter, Katsuhisa came under the governance of Oda Nobunaga, associating with the army led by Hashiba Hideyoshi to conquer the Chūgoku Region. In 1577, Katsuhisa was ordered to defend Kōzuki Castle, an auxiliary castle of Ukita Naoie in Harima Province, following its capture by Hideyoshi’s forces. In 1578, an army of 30,000 soldiers from the Mōri and Ukita clans attacked Kōzuki. At the time, Hideyoshi acted upon orders of Nobunaga to focus on attacking Bessho Nagaharu at the Siege of Miki Castle. Hideyoshi deployed his assistant, Kamei Korenori, to deliver a message to Katsuhisa and the defenders ordering them to retreat from the castle. Katsuhisa chose not to obey these orders and instead finally surrendered the castle after attacks by the Mōri forces. Katsuhisa, Amago Toyowakamaru (his eldest son), Amago Ujihisa (his older brother – the eldest son of Sanehisa), and Jinzai Motomichi (a senior retainer), all killed themselves. Katsuhisa was twenty-six years old.
Remnants of the army supporting the revival were led by Kamei Korenori. The Kamei were a branch of the Amago. Under the command of Hideyoshi, these forces participated in an attack on Tottori Castle and the deployments to the Korean Peninsula.
There is a story that, in a parting passage, Katsuhisa praised Yamanaka Yukimori for serving as a loyal commander of the Amago. Yukimori was taken prisoner, and later executed in transit to another location. This finale marked the end of the campaign to restore the Amago clan as a daimyō family.