Hamamatsu Domain
Inoue Masamoto was the eldest son of the previous "daimyō" of Hamamatsu Domain, Inoue Masasada. He became 8th head of the Mikawa-branch of Inoue clan and "daimyō" of Hamamatsu Domain on his father's death in 1786. He was awarded Lower 5th Court Rank and the courtesy title of "Kawachi-no-kami" soon afterwards.