Soak in Japan's three classic hot spring towns
Kusatsu, Arima and Gero have been called Japan's three finest hot springs since the 1600s, and each town has public baths you can use on a day visit without staying overnight. The water is different in each: strongly acidic in Kusatsu, rust-brown and salty in Arima, smooth and alkaline in Gero. Arima is about an hour from Osaka, while Kusatsu and Gero are better with a night at a ryokan.
A large open-air bath in Sainokawara Park, on the edge of Kusatsu, where hot water steams out of the ground along a stream. On Fridays the bath is mixed and everyone must wear a yuami-gi, a bathing gown; on other days men and women bathe separately. It is an easy walk from the town center.
A public bath in the center of Arima, filled with kinsen, "gold water", the rust-brown spring rich in iron and salt that Arima is known for. Afterward, walk a few minutes to the Tenjin spring source, where the water comes out of the ground at about 99°C. It is closed on the 2nd and 4th Tuesdays of the month.
Arima's other public bath, filled with ginsen, "silver water", a clear spring that feels nothing like the brown kinsen. A combined ticket covers both baths, so you can compare the two in one afternoon. It is closed on the 1st and 3rd Tuesdays of the month.
An open-air bath in the middle of Gero's hot spring town. Gero's water is alkaline, so it feels smooth and slippery on the skin, and every bath in town draws the same water. Gero is about an hour and a half from Nagoya by limited express train.
A small neighborhood bathhouse in Gero, open from the afternoon, where local people come for their daily soak. The tubs hold the same smooth Gero water as the big hotels. Check the city's list of baths for its open days before you go.