Some Japanese castles built during the Edo period had these kind of flooring in the hallways.
It is said that these specially designed creaking floors sound much like the bush warbler singing.
In English, they are known as nightingale floors.
Inside Ninomaru Palace of the Nijo castle where nightingale floors are installed.
Each clamp hastwo spike holesthrough which an iron spike goes through.
Photo credit:ERIC SALARD/Flickr
