Shiranui Legend

The Shiranui legend is a Kumamoto tradition of mysterious lights that appear over the Yatsushiro Sea (also called the Shiranui Sea) on the night of the last day of the seventh lunar month. The Nihon Shoki (720 CE), in the Keiko chapter, records that during Emperor Keiko's Kumaso campaign his ship was guided to a harbour off Ashikita by lights on the night sea; the name shiranui ('unknown fire') is said to come from this account. Until the modern period the lights were treated with reverence as ancestral or divine fires; later scientific work has identified them as a form of mirage in which fishing-boat lights are multiplied through atmospheric refraction. Local fishermen along the Yatsushiro coast traditionally called them 'ancestral fires'. Primary references are in the Nihon Shoki Keiko 18, with related notes in the Hizen no Kuni Fudoki and Bungo no Kuni Fudoki. Later scientific treatments by Miyaji Denzaburo and Terada Torahiko, and the folklore volume of the Kumamoto prefectural history, document the modern reception.