The area was designated the Chūbu-Sangaku National Park on December 4, 1934.
[1] Shimonoroka, or lower corridor,[citation needed] is the central Kurobe Gorge.
Shimonoroka can be accessed by using the Nichiden hodo (Nichiden Trail) or Suihei hodo (Horizontal Trail).
These trails are very dangerous; they can be only 20–50 cm wide and lie 500 m above the riverbed.
[2] Kaminoroka means Higher corridor.