Nightingale Floor: An Ancient Japanese Intruder Detection System

Squeaky floors are annoying, which is why when you search for “squeaky floors” in Google, you get hundreds of articles offering you tips and advice on how to make your floors squeak less. But in ancient Japanese societies, especially among royal families, squeaky floors were not hated but desired—because a floor that screeched and groaned with each step was an effective anti-burglar alarm system.

Some Japanese castles built during the Edo period had these kind of flooring in the hallways. They are known as uguisu-bari, where uguisu refers to the Japanese bush-warbler or the Japanese Nightingale—a very shy bird that prefers to stay hidden among the foliage, but its distinctive breeding call can be heard throughout much of Japan from the start of spring.

It is said that these specially designed creaking floors sound much like the bush warbler singing. In English, they are known as nightingale floors.

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While dry boards naturally creak under pressure, nightingale floors have extra metal clamps located between the beams that support the floorboards of the corridor. Each clamp has two spike holes through which an iron spike goes through. When someone walks over the boards, the clamp moves up and down causing the spike to rub against the clamp, producing a shrilling noise.

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Nightingale floor, Japan

Quite a smart idea, :)