The Japanese Developed Intentionally Squeaky Anti-Ninja Floors

In the days before accurate long-range firearms, assassination was a much more intimate activity. Just another way technology has stolen human connection from us, amirite? 

If you wanted to knock off the top block of your local power structure, you’d have to get in arm’s reach of the target — or at least their kitchen. In Japan, ninjas are the famous warriors known for their stealth, and you practically can’t picture one without having them tiptoeing down an ancient hallway. 

So when you were trying to thwart a master of silent movement like a ninja, you had to go farther than stringing up some bells to keep them from accessing important areas in the cover of night.

One invention in particular for any paranoid official was built right into the floor of their buildings, with the intent of giving an early warning that there was an ongoing attempt on their life. These were tiles known as uguisubari, or “nightingale floors.” The construction of these sections looked identical to any other bit of the floor, only betraying their purpose when weight was put on them. 

The wooden planks making up the uguisubari were intentionally loose, giving them vertical play as someone walked over them. Those up-and-down movements caused a metal clamp to rub against nails beneath the floor, which would let out a trademark “chirp,” apparently one very similar to the nightingale, which earned them their name. 

It was a brilliant bit of defensive architecture, outside, I suppose, of making political officials terrified of nightingales.