A Song in Silent Steps
Edo period of Japan, after the unification Japan was run by a semi-feudalistic system with many regional Lords or Daimyo commanding their own land and private armies. At this time of intrigue each Daimyo did tread most carefully along the delicate political threads. All were careful but tenacious, hoping to rise up the ranks and become stronger Daimyo. They did occasionally get it wrong though. With dire consequence.
Specifically assassination, by ninja. At this point in time the Ninja were unstoppable. Notoriously effective and using unknown techniques combined with pure trickery the had the power to seemingly strike any target at any time then disappear undetected like a deathly gasp of the wind. This understandably caused some upset to their targets, so a means was devised to detect their presence, even in the depths of night.
The Nightingale Floor, in Japanese Uguisu-bari (鴬張り).
The Nightingale Floor was a specially designed floor which sang. When a person places their weight upon it, the surface bends and warps, causing flooring nails to rub against a jacket or clamp, producing an audible low creak, vaguely reminiscent of a songbird’s chirping. This shattering sound against their silent footfalls would alert any guards and force the Ninja to flee from the floor’s song.
They were built and worked perfectly, some still function to this day; many were installed in the corridors of the rich and cautious whilst others were safeguards of treasures in many a temple. The most famous one however lies within Nijō Castle, a large fortification in the old Japanese capital, Kyoto.
Built during the Edo period it was the seat of Japan’s power, often home to many visiting Daimyo or Shogun(Military Commander). To protect the valuable guests there were many Nightingale floors installed in the corridors, and some rooms even had special doors in them where a Shogun’s personal bodyguard could lie in wait for any attackers who dared to venture across the Nightingale Floor.
To this day, the Nightingale floors twist chirp within Nijō Castle, mainly for tourists however I am assured that the place is still impenetrable to Ninja, which can only be a good thing.