Why is Xiushan Temple a hot spring in the history of Izu?

Xiushan Temple Hot Spring is located in Izu Peninsula in Shizuoka Prefecture, forming a hot spring street on both sides of Guichuan, which is the most historic hot spring in Izu. It is said that the master in Heian period discovered this spring, and the symbol of Xiushan Temple Hot Spring "Du Kabath Soup" is said to be the earliest source at that time. Now there are Xiushan Temple, the birthplace of hot springs, Xiushan Temple in the center of hot springs, The Old Inn, ancient buildings and Huxi Bridge above Guichuan, all of which are like old hot springs.