According to the Engishiki (codes and procedures on national rites and prayers), one officer at a time from the Shonagon (lesser councilor of state), Benkan (oversight department), Geki (Secretary of the Grand Council of State) and Shi (Officials in charge of records) each held the position of Betto as the person in charge concurrently with their normal position.
延喜式によれば、責任者である別当（べっとう）は少納言・弁官・外記・史_(律令制)からそれぞれ1名が兼務した。