While Chokan, Tsuhangan and Hangan were formal officials called 'Ryunaikan,' most of Sakan were 'Ryugaikan' (miscellaneous posts to which ordinary people were appointed), who were not formal officials and were not included in Kuhonkan (nine official posts).
また、長官・通判官・判官のいずれもが正式な官人である「流内官」だったのに対し、主典のほとんどは「流外官」（庶民が登用される雑吏）であり、九品官には含まれない正式な官人ではなかったのである。