"Isetsu machimachi," an essay written by Masamichi WADA, who was a feudal retainer of Sekiyado Domain, describes that in Izumo Province (the present-day northeast part of Shimane Prefecture), when they went into a valley where a stream was running under the bridge on one of the days under the long spell of rainy and humid weather, people experienced a situation where white lights were flying like butterflies and once they adhered to people's body, they could not be easily taken away.
関宿藩藩士・和田正路の随筆『異説まちまち』によれば、出雲国（現・島根県北東部）で雨続きで湿気が多い時期に、谷川の水が流れていて橋の架かっているような場所へ行くと、白い光が蝶のように飛び交って体に付着して離れないという。