The Šance mountain (originally Turecký vrch or Türckner Berg) represents yet another important element of the Jáchymov silver district. Extraction commenced here immediately after the foundation of Jáchymov, the results still visible in the many old sink-holes and collapsed adits. At the same time, this area provides an illuminating insight into how the mines were supplied with water from the 16th century onwards. This is because the Gegenbau adit (with its mouth on the eastern slope of the mountain) and the Dürrenschönberger adit (which opens to the west below the Jáchymov town pond) cut through the entire mountain. They served as leats which led water flowing through the irrigation channel from the Neklid or Unruh adit below Boží Dar into the chamber of the Einigkeit mine. The total length of the watercourse, including its underground sections, was over 4 kilometres. The Gegenbau and Dürrenschönberger adits are still used for water-management purposes today.