Sekigane Onsen Seki no Yu Public Bathhouse is a historic communal bathhouse located in Sekiganeshuku, Sekigane-cho, Kurayoshi City, Tottori Prefecture. Sekigane Onsen is said to have been discovered approximately 1,300 years ago by the monk Gyoki and later developed by Kobo Daishi. Its waters boast the second-highest radon content in Japan, surpassed only by Misasa Onsen in Okayama Prefecture, and are nicknamed the Hakkin no Yu (Platinum Bath) for their beautiful clarity. Seki no Yu was built in 1903 (Meiji 36) by local residents as a community bathhouse, and has been beloved by locals for over 120 years. The water quality is simple weak radioactive spring (radium spring), served as 100 percent free-flowing source water without any heating, dilution, or chlorination. The wooden bathtub accommodates only 4 to 5 bathers at a time, and admission is an affordable 200 yen. Known for its efficacy against neuralgia, joint pain, gout, and digestive disorders, it remains a hidden gem cherished by locals and onsen enthusiasts alike.