Warning system for sophisticated intrusions of feudal Japanese people

Perhaps no intruder (and failure) in history is happy with the likes of old Japanese guests. Rather than enduring the sudden squeal of ear-splitting ears from expensive electronic bells, they will enjoy the last moments of their life chirping from the legendary anti-intrusion system in architecture. Japanese feudal: Hallway warbler.

The warbler corridor , called "uguisubari" , is a floor system designed to emit a distinctive sound when someone sets their feet up.

Hallway warbler.

Used in the corridors of temples and palaces, this system emits chirping as if the birds sing, helping alert the guards of the building and forcing those who like guests to abandon the intrusion of me

The word "warbler" in Vietnamese corresponds to the word "uguisu" , a Japanese warbler bird or living in bushes. So "uguisubari" translated into Japanese means "warbler guard".

This system emits a chirping sound like a bird singing.

A close look at the mechanism of the warbler corridor at Chino-in Temple, Japan:

The Eikan corridor of the Warbler-dō Zenrin-Ji.

The most famous place in Japan with such a corridor design is in the Ninomaru palace of Nijo castle in Kyoto. According to Japanese legend, these corridors were designed to help guards identify the intrusion of ninja, thereby blocking the famous assassins with this mysterious and silent practice.

In addition, they are also used to protect the temple's fortune. Built during the Edo period, Nijo castle focused on supreme political power in Japan, when many officials and military generals used to live here. The Warblers corridor is still used today, to protect important guests from visiting this place.

These floors emit a characteristic chirp whenever pressure is applied.

Ninomaru Palace at Nijo Castle.

When a Shogun (Shōgun) or Lord (Daimyō) visits the castle, their rooms all have special doors where guards and guards are always standing and ready to fight any intruder.

This effective but also very sophisticated intrusion warning system was invented by the best carpenters and craftsmen in Japan at the time.

To build a corridors of warblers, wooden planks are placed on a supportive frame, both solid enough to not dislocate from the shaft, just loose enough to slightly swing when being stepped on. So whenever the intruder's footsteps touch the floorboards, the floor connectors rub against the wooden beams and create the famous chirping,

Simple techniques of wood and nails provide maximum efficiency.

Temple of Chion-in.

Using special carpentry techniques even helps determine the location of the intruder by the loudness of the sound.

In addition to Nijo Castle, the Warbler Hall can also be found in Chion-in Temple, Eikan-do Temple-Zenrin-Ji Temple and Shingon Buddhist Temple Daikaku-Ji, all located on in the capital of Kyoto, Japan.