This is the only mine tunnel of the Iwami Ginzan Silver Mine Ruins that is regularly open to the public. It was developed in the middle of the Edo period. Along this 600-meter-long tunnel, you can still see the traces of the chisels that the miners used to chip away at the rock, as well as a 100-meter-deep pit dug for drainage, giving you a vivid image of what it was like in the days when silver was mined here.