Hamamatsu Domain
Matsudaira Sukemasa was the third son of Matsudaira Sukekuni, the "daimyō" of Yoshida Domain in Mikawa Province. On the death of his father in 1752, he became "daimyō" of Hamamatsu Domain and head of the Okōchi-branch of the Matsudaira clan at the age of eight.