I visited Atosanupuri, also known as "Sulfur Mountain," back in 2021, and I was amazed at how close we could get to the vents. The mountain is barren, with over 1,000 vents spewing steam into the air, filling the surroundings with a distinct sulfur smell. This mountain, a vital source of hot springs for the famous Kawayu Onsen, has long been cherished by locals.

Hiking:

If you want to hike around, there's the Tsutsujigahara Nature Trail, starting at the Kawayu Eco-museum Center, offers a 60-minute hike to Mt. Io’s slopes. The trail showcases dramatic vegetation shifts due to increasing soil acidity, transitioning from lush Sakhalin spruce and Japanese oak forests to lowlands dotted with Japanese stone pine and marsh Labrador tea. In June, the marsh Labrador tea blooms into a striking carpet of white flowers.

History:

Once a thriving site for sulfur mining, the area played a key role in the development of Teshikaga town, with a railway built to transport the sulfur. Today, you can learn about this history at the newly renovated MokMok Base, which reopened in 2023.