In medieval Japan, some castles (and other buildings) were constructed with special floors that made a squeaking or chirping sound to alert the residents to intruders (or anyone else) walking across the floorboards.
Visitors can still see and experience these “nightingale floors” at a number of Japanese landmarks, including Nijo Castle in Kyoto. In fact, that’s where I’m headed today (remember…I’m in Japan!). I’m planning to get some photos and, hopefully, video to share here on the blog when I return.
Modern myths claim these floors were designed to prevent shinobi (aka “ninja”) assassins from harming the occupants. If a ninja tried to cross the floor at night, either alone or as part of an attacking force, the singing floors would alert the watchmen and other occupants of the house or castle.
In reality, foiling assassinations was only part of the reason for these special floors. During the medieval era, wealthy samurai faced many threats, and ninja assassins were only one. Thieves were as big a threat then as now (if not more so, in some cases), as were sneaky or nosy guests, as well as clandestine, midnight attacks by many different kinds of enemy forces.
Squeaking floors could alert a host to guests moving through the house in the night, but also gave notice of servants walking in places where they didn’t belong, and even teenagers sneaking out for clandestine “adventures” — a problem which has existed as long as teenagers have!
The special, “singing” floors were called uguisubari, which translates “nightingale floors,” because of the chirping noise the floorboards made.
The full, literal translation is “floor with the sound of a nightingale from the straining floorboards” – but “nightingale floors” gets the idea across without the extra verbiage.
Architecturally, the floors were constructed with nails positioned to rub against a metal jacket or clamp when someone or something placed pressure on the boards. If you’d like to see (and hear) these famous floors, there are several good videos on YouTube.
In modern times, people spend a lot of time and money to ensure that hardwood floors are properly “de-squeaked” and that family and visitors can walk across them without a sound. We’ve moved from squeaky floors to less immediately intrusive electronic alarms for doors and windows. However, if you consider the ingenuity involved in constructing an effective alarm for houses without the benefits of electricity or other modern conveniences, I think you’ll agree the nightingale floors are a pretty ingenious solution.
Finding a way to create an alarm without the benefits of modern bells and whistles (literally as well as figuratively) is a clever and intricate example of architects using design to solve a real-world problem.