Lifespan: Meiō 6 (1497) (?) to 4/6 of Tenbun 3 (1534)
Title: Director of the Imperial Cavalry of the Left Division
Father: Satomi Yoshimichi
Siblings: Yoshitoyo, Yoshifusa
Children: Obara Sadamichi, Iemune
Grandchildren: Yoshimune, Nakazawa Tadamune
Great-grandchildren: Munemoto, Nakazawa Tadashige
Great-great-grandchildren: Munesuke, Nakazawa Yoshitora
Satomi Yoshitoyo served as a daimyō during the Sengoku period. He was the fourth head of the Satomi clan of Awa Province.
Yoshitoyo was born as the lineal heir of Satomi Yoshimichi, the third head of the Satomi clan.
The interpretation the events leading up to the death of Yoshitoyo at the Battle of Inukake and his succession by Satomi Yoshitaka has evolved over time. Formerly, the longstanding story was that the banal Yoshitoyo murdered his uncle, the innocent Satomi Sanetaka, so Yoshitaka killed him in revenge. A more recent theory is that Yoshitoyo was attempting to thwart a coup d’état led by Sanetaka and Yoshitaka (father and son) after they combined forces with Yoshitoyo’s archrival, Hōjō Ujitsuna. The confusion in records is deemed owing to fabrications in later years to conceal the fact that Yoshitaka usurped the role as head of the clan from Yoshitoyo and soon thereafter betrayed the Hōjō clan.
Prior interpretation of events
In 1518, Yoshitoyo inherited the headship of the clan after his father, Yoshimichi, became critically ill. Until Yoshitoyo became fifteen years old, his uncle, Sanetaka, served as his guardian and proxy in battle. Around this time, to resist the Hōjō clan who advanced to the Miura Peninsula on the opposite shore, in 1526, Yoshitoyo joined Sanetaka in attacks on Shinagawa and Kamakura, demonstrating his skills in an event known as the Battle of Tsurugaoka-Hachiman Shrine. Nevertheless, even after Yoshitoyo reached the age of fifteen, Sanetaka did not cede authority to him. Moreover, a senior retainer named Masaki Michitsuna (Tokitsuna) approached Sanetaka and, after beginning to have a prominent voice in the family, stirred resentment among other senior retainers. As a result, in 1533, Yoshitoyo attacked and murdered Sanetaka and Michitsuna at Inamura Castle. There is also a theory that Michitsuna managed to escape but died later of his injuries. Under the banner of avenging the death of his father, Sanetaka’s eldest son, Satomi Yoshitaka, joined with Masaki Tokishige (the orphan of Michitsuna) and rebelled against Yoshitoyo. In the course of a conflict that ebbed and flowed, Yoshitoyo initially defeated Yoshitaka, but Yoshitaka then counterattacked, driving Yoshitoyo to Kazusa Province. The next year, Yoshitoyo received support from Mariyatsu Jokan (Nobukiyo) of the Takeda clan and returned to Awa, but at the Battle of Inukake, incurred a major defeat and took his own life. He was twenty-one years old. This is referred to as the Inamura Incident or, alternatively, as the Tenbun Discord.
Current interpretation of events
Based on documents issued by Yoshitoyo during the Eishō (1504 to 1521) and Daiei (1521 to 1528) eras (with the oldest dating to 1512), there is a strong likelihood that Yoshitoyo had completed his coming-of-age ceremony by the time that his father, Satomi Yoshimichi, had died. This raised suspicions that previously known records indicating that Sanetaka served as a guardian of the Satomi clan and proxy of the head of the clan during deployments were fabricated to justify the succession to the headship of the clan by Yoshitaka. In fact, it appears that, after Yoshitoyo learned of contacts between Sanetaka and the rival Hōjō, Yoshitoyo had Sanetaka and his associate, Masaki Michitsuna, killed in an effort to preempt a coup d’état. Based on the fact that the oldest existing document was issued twenty-two years before the death of Yoshitoyo, it is surmised that Yoshitoyo was over thirty years old at the time of his death and, as such, did not require the guardianship of Sanetaka as explained in other documents. In addition, the prevailing view is that Inamura Castle served as Yoshitoyo’s residence from the beginning.
On 12/23 of Daiei 7 (1527), Yoshitoyo awarded the status of a craftsman for metal casting to Ōno Daizen-no-suke of the Yana township in the Sugō manor of Kazusa Province in an effort to meet his own needs for metal works.