Watarase Onsen Tanabe

Watarase Onsen in Tanabe city, within the Hongu district of the Kumano mountain heartland of Wakayama Prefecture, is renowned throughout Japan for possessing one of the country's largest outdoor rotenburo — a series of immense open-air sulfurous pools carved from the riverside terrain of the Totsu river valley, including a massive mixed-gender outdoor bath surrounded by forest and mountain scenery of exceptional atmospheric power. The sulfurous waters, rich in hydrogen sulfide from the volcanic geology of the Kii Peninsula, are traditionally valued for their skin-beautifying and musculoskeletal benefits, and are prescribed in Japanese thermal medicine for rheumatic and cardiovascular conditions. The Kumano Kodo UNESCO pilgrimage routes pass through the surrounding forest, and the Hongu Taisha grand shrine stands within a short walk of Watarase, embedding this onsen in one of the most spiritually resonant landscapes in the Japanese archipelago.