Focusing on the Hirabutai of Itsukushima Shrine, this study reexamines the conventional idea that the disaster mitigation measures were taken to reduce the damage by making it a "raft structure". The fact that the columns and girders of the flat stage were not connected by a clamp or similar means makes it more natural to assume that the flat stage was consistently surfaced when it could not follow medium term changes in the tide level, and it is unlikely that this was a proactive disaster mitigation design aimed at protecting the main shrine from damage by surfacing the flat stage.
