Located in Hayakawa Town, Minamikoma District, Yamanashi Prefecture, Keiunkan is a hot spring ryokan with a history dating back to 705 AD (Keiun 2). It was certified by Guinness World Records as the oldest hotel in the world in 2011. The inn was founded when Fujiwara no Mahito discovered hot spring water gushing from between rocks in a river during a hunting trip and built a bathing facility. The establishment has been operated by 52 generations of the same family. Guests can enjoy six different baths fed by four naturally flowing source springs. The water quality is sodium-calcium sulfate-chloride spring (low-tension alkaline high-temperature spring) with a pH of 9.36 and a source temperature of 52 degrees Celsius. The total flow rate is an impressive 2,030 liters per minute (1,630 L/min from drilled artesian wells plus 400 L/min from natural springs). The entire facility uses 100% free-flowing natural source water without heating or dilution, including guest room baths, hot water supply, and showers. The water is colorless and transparent with a faint mineral scent, known for its skin-beautifying effects. Nestled deep in the gorges of the Southern Japan Alps, guests can enjoy bathing while taking in the spectacular seasonal scenery of the valley.