Komatsu Jigoku Hell is located within the Aso Kuju National Park in Oita Prefecture. The place is named so due to the red rocks, steam, and hot, bubbling mud that have resulted from volcanic activity. The spot is equipped with a path that visitors can use to walk around and view the area, only about 20 minutes from start to finish. Due to the geothermal heat and steam, it is warm all year round, and it smells of sulfur from the hot springs.
Located nearby the walking path is the Hatchobaru Geothermal Power Plant, which utilizes geothermal power. The area is also home to Suijyu Onsen, which is popular for a rather unusual reason: visitors can cook eggs here. If visitors bring their own raw eggs, they can put them in a basket attached to a long stick and use the hot spring steam to make “onsen eggs,” which only takes about 9 minutes. Another famous dish of Suijyu Onsen is gokuraku ondori, which is made by taking fresh, local chicken, stuffing it with cabbage and onions, and steaming it in the natural hot spring holes.