Lifespan: Genchū 6 (1389) to 9/13 of Ōnin 1 (1467)
Other Names: Tarō (common)
Title: Governor of Echigo
Clan: Nasu (Lower Nasu family)
Father: Nasu Sukeshige
Children: Sukezane, Okino Mochitaka
Nasu Sukemochi served as a bushō during the mid- to late-Muromachi periods. Sukemochi was the head of the Lower Nasu family and the lord of Karasuyama Castle in the Nasu District of Shimotsuke Province.
Divisions in the Nasu clan
Following the formation of the Kamakura bakufu in the late twelfth century, the Nasu became direct retainers of the bakufu and witnessed their peak period of prosperity during the Muromachi period. Along with the Yūki, Satake, and Utsunomiya clans, the Nasu were counted among the Eight Houses of the Kantō. In the 1440’s, the Nasu clan split between the upper and lower halves, known as the Upper Nasu family and the Lower Nasu family, entering a period of decline. Thereafter, the Upper Nasu family relied upon the Muromachi bakufu while the Lower Nasu family turned to the Kamakura kubō (later the Koga kubō) for support in an ongoing struggle against one another. In 1514, internal conflict resulted in the demise of the Upper Nasu family, enabling Nasu Sukefusa of the Lower Nasu family to unify the Nasu clan. The unified clan then engaged in persistent conflict with the Utsunomiya and Satake clans. In 1590, Nasu Sukeharu was late in deploying for the Conquest of Odawara led by Toyotomi Hideyoshi after which his landholdings were seized. Owing to an apology from a retainer named Ōtawara Harukiyo (a daimyō), Sukemochi’s son, Nasu Sukekage, was granted a fief of 5,000 koku and narrowly avoided being removed from his position.
Sukemochi was born as the son of Nasu Sukeshige, the head of the Lower Nasu family.
Sukemochi was in conflict against Nasu Ujisuke of the Upper Nasu family following its split from the Shimo-Nasu in the era of Sukemochi’s father. In 1438, during the Eikyō Conflict, Sukemochi backed Ashikaga Mochiuji (the Kamakura kubō) and during the Kyōtoku War beginning in 1455, joined Mochiuji’s son, Ashikaga Shigeuji, to oppose the Uesugi and the Shimotsuke-Utsunomiya clans.
Upon demand of Shigeuji, on 4/19 of Kyōtoku 4 (1455), he attacked Motegi Castle in the Haga District of Shimotsuke. On 5/1, he solidified defenses against Utsunomiya Hitotsuna who rebelled. He further received a letter from Shigeuji angrily criticizing Hitotsuna for the rebellion.
Sukemochi’s lineal heir, Nasu Sukezane, inherited the headship of the clan while his second son, Okino Mochitaka, founded the Okino as a cadet family.