Follow the path back toward the main road. If you listen closely on your left, you may hear a small buzzing or popping noise. That is the sound of the small Suzume Jigoku, or Sparrow Hell, whose escaping steam is said to sound like the chirping of small birds.
　There is a story behind this name. It is said that in the 1570s, one of the young monks training at a temple in Unzen had a prized white sparrow. He refused to share the company of his sparrow with some other monks on the mountain and was killed in the resulting fight. This sparked an even wider battle among the monks studying at Unzen that ended in the destruction of many of the temples. In the chaos, the prized sparrow fell into this jigoku, which takes its name from the bird.