Hike to all the onsens in the park. (From 10,000 waves tours: "Nyuto is contained within the Towada-Hachimantai National Park. A mountain trail connects all seven Nyuto onsens, and you can hike the whole thing in about two hours, stopping for a dip in each bath and taking in the particular properties of the various waters. (Each pool is said to confer a unique benefit.) "