Tonbara Ramune Ginsen is a hot spring with a rare spring quality: carbon dioxide-sodium-bicarbonate chloride spring. The source temperature is low at about 14.6°C, so it is heated, but the water in the bath is still lukewarm for a hot spring, at 38-40°C. However, when you take a sip of the water gushing out of the spout, you can feel the delicious salty carbonation with a slight hint of iron, and it is literally as refreshing as Ramune. This carbon dioxide gas adheres to the skin, which is said to promote blood circulation and make the skin smooth after the bath. You can enjoy a mysterious bathing experience that warms you from the core even at low temperatures.

This hot spring is a historic hot spring with a history of being bottled and shipped as drinking Ramune water during the Meiji era, and in 1881 it received an award at the World's Fair in Germany as "the world's rarest silver spring." The spring water is clear and colorless, but after coming into contact with air it changes color from green to yellow to orange over the course of about three weeks, so you may be able to enjoy a different color every time you visit.