Castles In Ancient Japan Incorporated This Bizarre Feature To Guard Against Invading Ninjas

Throughout the centuries in Japan, highly skilled craftsmen have made a stunning mark on its landscape. Exquisite castles, once the homes of Japanese daimyō, speckle the countryside. And yet an unusual sound echoes around their elaborate hallways and corridors. A kind of birdsong chimes from the movement of the floorboards with every footstep. But there’s a clever purpose behind the chirping.

From 1603 to 1868, Japan was ruled by the Tokugawa shogunate; the era was known as the Edo period. It was an era of intricate civil arrangements, in which everyone knew their social status. Emperors ruled the land, yet they wielded little actual power themselves. They, however, were supported by a cast of shōguns, daimyō and lords, who numbered in their hundreds.