Traditional onsens – hot spring baths – are a staple of Japanese culture. | BBC Travel

"Tamagawa Onsen in Semboku City, Akita Prefecture, boasts the highest output of spring water from a single site in Japan (9,000 liters per minute), as well as the most acidic spring water with a pH of 1.2♨ The hot spring is mainly composed of hydrochloric acid, which is rare in the world, and is said to promote natural healing✨ There are 11 types of baths in the large public bath, including a hot spring with a 100% spring source, a weakly acidic hot spring, and hot and warm baths at different te