Tokusa Onsen derives its name from the tokusa (common horsetail plant) which is abundant in the region. It was discovered as a hot spring source approximately 1000 years ago, and has long been known as "Aizu's hidden hot spring". In the public stone outdoor bath, where the hot spring rises directly from the riverbed, you can heal your heart and body while listening to the soft murmuring of the clear stream, which has been unchanged for ages. There are more than 16 ryokan inns and pensions dispersed throughout the Tokusa Onsen region, and it is widely known as the "hamlet of the hidden hot spring". You can take a tip in the stone public bath 24 hours a day, but please be mindful that onsen use is not segregated by gender, nor is it shut off from public view! Not for the faint of heart.