According to Japanese beliefs, byōbu nozoki is a depraved spirit which emerges from the decorative folding screens known as byōbu. It is very tall, stretching well over two meters (tall enough to peer over any sized folding screen). It’s body is long and lithe, and it wears white robes resembling those of a ghost. It has long black hair and blackened teeth. Despite the resemblance, byōbu nozoki it is not a yūrei, but is actually the tsukumogami of a folding screen.

As its name suggests, a byōbu nozoki’s chief activity is leering over folding screens at the people on the other side — particularly if the people are engaged in romantic activities.

Byōbu nozoki was invented by Toriyama Sekien for his book "Konjaku Hyakki Shūi" (今昔百鬼拾遺, "Supplement to The Hundred Demons from the Present and the Past", 1780). According to him, this spirit manifests from a very old folding screen which has witnessed many years of sexual activity.

Sekien invented a fake history connecting it with Chinese history. Sekien describes the byōbu nozoki as tall enough to peer over a folding screen seven shaku (a unit of length approximately 30 cm) high. This recalls a story about the Chinese emperor Qin Shi Huang, in which he leaped over a 7 shaku tall byobu to escape an assassination attempt. This legend which would have been well known to his readers during the Edo period. With this reference, Sekien both invents a funny narrative and finds a way to connect this amusing yōkai with history, legitimizing it as more than something he just made up.