20 Ryokan in Tokyo and Surroundings

They have two large bathhouses, one a sulfur spring without hydrogen sulfide, the other a Helston mineral bath. At 20:00 they switch the bathhouses for men and for women, so you can enjoy both on the same day. The large open-air baths are open alternately for men and for women. They also have an open-air bath which can be reserved for private bathing.