Kyoto was the capital city of Japan during the Middle Ages.
It was the home of the shogun, or Japanese military ruler. Nijo Castle was built in Kyoto in 1603. It has more than strong walls and a moat to protect the shogun, it has a squeaking floor, too!
The floors of the outer rooms at the castle squeak whenever someone steps on them. The squeaking sounds much like the singing of the nightingale. But the floors weren’t designed that way because the shogun liked to hear birds singing.
The shogun at the time was very fearful for his life, and the squeaking floors were designed to alert the ruler if anyone approached his chambers.