According to legend, Shibu Onsen’s Number 3 bathhouse has water that can heal cuts, boils and acne. Natural hot springs supply the water to the nine public baths of Shibu Onsen and each has a unique mineral composition. Matsu No Yu and the other public bathhouses have been maintained by locals for centuries since its reported beginnings in the 14th century. In the Edo period, these hot springs were used as a private spa for the Sanada Clan’s samurai retainers. Only overnight guests at Shibu Onsen’s ryokans (Japanese inns) can access these baths by borrowing a common key. Men and women have separate baths.