Sokokura Onsen is one of the historic Hakone Seven Hot Springs, known since before the Edo period. Kanrei is a distinctive day-use hot spring facility housed in a Western-style building from the Meiji era that once served as a medical clinic. It features a single open-air bath surrounded by bamboo groves along a mountain stream, available in a private reservation style for one-hour sessions. The sodium chloride spring water flows directly from the source, maintaining its natural mineral composition. With a source temperature of approximately 70°C, the water is adjusted with cold water to a comfortable bathing temperature, producing clear, refreshing water with a gentle touch on the skin. Tucked away from the main thoroughfare of Miyanoshita, the facility offers a peaceful respite far removed from Hakone's tourist bustle. The unique atmosphere created by the Taisho-era retro Western architecture, verdant bamboo groves, and the murmur of the mountain stream has made it a quietly beloved hidden gem among hot spring enthusiasts. Reservations by phone are required before visiting.