Masayasu was the son of hatamoto Inaba Masakichi, from whom he inherited the 5000 koku territory of Aono han in 1656. He served as a page and clerk for some time, before being summoned by the shogunate to oversee irrigation projects in the provinces of Kawachi and Settsu.
Masayasu was the son of a high-ranking hatamoto Inaba Masakichi, inheriting the 5000 koku territory of Aono han in 1656. He held various positions before being called upon by the shogunate to manage irrigation projects in the provinces of Kawachi and Settsu.