The different size of moats were probably representing how strong a chieftaincy's controlling power was over wet-rice cultivation in the area, how tight the community was united, or the difference in villager classes who lived inside and outside the moat.
水稲農耕に必要な首長権力や、共同体の結束強化、内部と外部での階級差を反映しているとも考えられている。