 His courtesy title was "Ukyō-no-daifu", later "Inaba-no-kami", and his Court rank was Junior Fifth Rank, Lower Grade.Tatsuaki was the second son of Tamura Muneyoshi, the "daimyō" of the 30,000 "koku" Iwanuma Domain.He underwent the "genpuku" ceremony in 1660 and was received in formal audience by "shōgun" Tokugawa Ietsuna, who confirmed him as heir to Iwanuma.