Mitsui Hachirōemon (三井 八郎右衛門) is the inherited name given to the first son born to the head family (総領家, Sōryō-ke), or the leading branch of the extended Mitsui family. It was Mitsui Takatoshi (三井高利) who started the naming ritual that a male heir would be called Hachirōemon when they decide the next leader of family business that Mitsui was known for. For those sons of Takatoshi, each bloodline had a nickname: the first son Takahira held the Kita branch, the second son Takatomi the Isarago branch (伊皿子家), and the third son Takaharu the Shimmachi branch (新町家).