Kaidan (怪談), literally "weird tale," is a Japanese tradition of supernatural storytelling dating to the Edo period. It grew out of an oral form in which people gathered to tell one tale after another, narrating an ordinary slice of life in a calm voice — without exaggeration or screaming — until it arrives, only at the end, at a chilling truth.
The essence of the form is restraint. Rather than showing the horror head-on it leaves it aslant, by implication, withholding explanation so the reader fills the gap themselves. It is a distant prototype of modern quiet horror that builds fear through mood alone, and one root of the manner in which record and recitation slowly summon the uncanny.