A Study on the Layout and Structure of the Cloister of Itsukushima Shrine from Hydrodynamic Aspects

Based on the findings of various previous studies on Itsukushima Shrine, this study focuses on the “cloister,” which contributes greatly to the creation of the shrine’s headland landscape and the mitigation of natural disasters brought by the sea. This paper reviews and reexamines previous discourses and discussions on landscape creation and responses to natural disasters. The paper reviews the history of the construction of the sea shrine pavilions at Itsukushima Shrine and examines the measures taken to mitigate the impact of the sea on the shrine pavilions, including the cloister, based on the sea conditions. As a result of this study, it was found that the screened corridor contributes to mitigating the buoyancy caused by the rising sea level during the storm surge by about 6%, and the wave transmission coefficient is about 0.3 for a wave with a period of 3.5 s, if the floor of the corridor is considered as a submerged flat plate and the screen is ignored. Therefore, the floorboard of the corridor is expected to reduce the energy of the short-period transmitted waves to the main building behind the corridor. However, it is difficult to accept the idea that the floorboards of the corridor were designed to reduce the energy of the waves.