Don’t let the fact that Niwa no Yu is located next to the dreary Toshimaen amusement park put you off. This is the nicest of Tokyo’s mega-onsen bathing complexes. Also, this boasts a 1,200 square-metre garden designed by famous Japanese landscape architect Kenzo Kosugi. To add, the natural hot spring water is gushing from 1,445m below ground and rich in sodium chloride. It is said to help heal neuralgia and muscle and joint pain. They’ve even ‘softened’ the water to prevent irritation of the skin. Besides hot-spring baths and sauna, Niwa no Yu also has a Bade zone (swimsuit required). Bade zone is a traditional German warm bath treatment that incorporates oriental massage. Bade zone hot water is set to match body temperature, and the bouyancy of the water aids in stretching and massaging the body. Since no kids are allowed, you are guaranteed some real peace and quiet.