The Nanataki course is the longest of the normal trails to the summit of Mt. Iwate. The name means 7 waterfalls, as during the first part of the trail, you indeed pass numerous beautiful waterfalls. After climbing out of the forest, you pass through a rather thrilling volcanic area with sulfuric gas steaming out of crevasses, after which you enter an alpine forest before finally emerging into the barren volcanic area around the summit. This is a somewhat challenging though extraordinarily rewarding hike recommended for experienced hikers (and the favorite of this hiker). Be sure to bring a map or at least check maps in advance, as there are a couple of forks along the way.