Why Do Elders Always Say 'Don't Cut Your Nails at Night'? Deconstructing a Century-Old Superstition in Taiwan, Japan, and Korea

1. Core Taboo and Origins: In Taiwan, Japan, and Korea, a folk taboo against 'cutting nails at night' is prevalent. Its most practical origin stems from insufficient lighting in ancient times; using sharp tools to trim nails in dim conditions could easily lead to accidental cuts. Elders warned against this for safety. This taboo has persisted for over a century, with clear written records appearing in Japan as early as 1915. 2. Regional Variations: • Taiwan: Besides the risk of cuts, superstitions extend to 'losing one's soul,' 'cutting away financial luck,' or 'never seeing one's parents one last time.' • Japan: The most famous saying is 'never seeing one's parents one last time,' originating from the phonetic similarity between 'yoru no tsume' (night nail) and 'yo-tsume' (end of life/shortened lifespan). Different regions have variations such as premature death, illness, or home burglaries. • Korea: A traditional folktale warns that if discarded nail clippings are eaten by a rat, the rat will transform into the owner's likeness and steal their identity. Modern Medical Advice: Modern medicine states that nails can be cut at any time; the method is key. The American Academy of Dermatology (AAD) recommends trimming after bathing or soaking when nails are soft. Fingernails should be trimmed nearly straight across and the sides rounded. Toenails should be cut straight across to prevent ingrown nails, and the cuticle, which protects the nail root, should not be arbitrarily removed.