As a mountain worship venue, Dewa-Sanzan (the Three Dewa Mountains), which attracts many monks who lead an ascetic life in the mountains and worshippers, is the collective name for Mt. Gassan, Mt. Hagurosan and Mt. Yudonosan spread over the Shonai area in Yamagata Prefecture. Mountain worship has existed in Japan in the form of folk beliefs since times of yore and climbing the Dewa-Sanzan became popular among the general public as “A Journey of Rebirth” during the Edo period. This old Japanese tradition continues to link faith with the natural mountain environment to this day.