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. for this, he was awarded the post of "wakadoshiyori" in 1682, and had his lands expanded to 12,000 "koku". masayasu visited kyoto as part of a formal inspection in 1683. in this period, masayasu's cousin, inaba masamichi, held the powerful and highly trusted position of kyoto "shoshidai".