Kōsatsu
The Kōsatsu (, literally "High plaque"), also called Seisatu (, literally "Controlling plaque"), was the public notice of the han-lord's or shogun's proclamations in the Japanese history.Kosatsu (SamuraiWiki) They were the local or nationwide laws written on the wooden plate, placed in the kōsatsu-ba of the shukuba or sekisho (関所), the border between han, where there was frequent traffic.