Ipponmatsu Onsen Tatsuko-no-yu is a completely wild hot spring (noyu) located in the Nyuto Onsen area of Senboku City, Akita Prefecture. Situated along the hiking trail to Mount Nyuto (1,478m) within Towada-Hachimantai National Park, it's located just above where you cross a tributary of the Ipponmatsu River. While there used to be a hot spring inn here, it's now a pure wild hot spring with no changing facilities. The bathing pool accommodating 2-3 people is a foot-spring where hot water bubbles up from the bottom. Since the source temperature is high, visitors can adjust the temperature by using a hose to bring in stream water. The water is transparent but turns milky white when the hot spring mud at the bottom is stirred up. The area has a sulfur aroma and offers particularly beautiful scenery during autumn foliage season.