According to the legend, 'Arimitsu had a dream that while he was praying for Hachimanjin (the god of Hachiman-gu Shrine) day and night looking for the best place for his political base, he found a place with three reeds, where a spring was flowing.'
伝承によれば、「有光は八幡神に日夜祈りを奉げてより適した場所を探していると、蘆が三本生えるところに清水が湧き出している夢を見た。」とある。