Sachuben was considered the first step on the ladder of the promotion to Third Rank or above, as the officials who served as Sachuben or above were qualified to be promoted to Sangi, but those who served as Uchuben and below were not qualified.
左中弁以上の経験者には参議に昇進する資格があり（右中弁以下にはない）、将来三位以上に昇る道が開かれた出世の登竜門であった。