At the time of Genko, Japanese people were scared by the attacks of the Mongol and Goryeo army, saying, 'moko kokuri no oni ga kuru' (the devils of the Mongol and Goryeo will come), which phrase later came to represent something scary, and thus a tradition spread to the whole country to scare children by saying 'mukuri kokuri, oni ga kuru' to make them behave themselves.
その後の日本では、元寇の時、蒙古・高麗軍が日本を襲ったことを、「蒙古高句麗の鬼が来る」といって怖れたことから、転じて恐ろしいものの代表として子供の躾けなどで、「むくりこくり、鬼が来る」とおどす風習などとなり全国に広がった。