The Kama Tunnel
The Kama Tunnel provides the only vehicle access to the remote Kamikochi valley. The tunnel was named for the spray rising from the rapids of the nearby Azusa River, which is said to resemble steam rising from a boiling cauldron (kama).
The tunnel is frequently closed due to landslides and avalanches, although the structure is periodically improved to protect it from damage. The tunnel was first dug by manual labor in 1927, and served mainly as a transportation route for the power industry. Bus services offering visitor access began in 1933, and were expanded to include Kamikochi in 1935—an important step toward the designation of the area as a national park.
The tunnel was further improved in 1937, and remained in service until the current tunnel was opened in 2005. The tunnel is narrow and steep and also has a sharp curve partway through. An increase in traffic congestion from tourists visiting Kamikochi led to private cars being banned from using the tunnel in July and August from 1975 onward. From 1996, the ban was set year-round. Buses and taxis are allowed through for most of the year, but the tunnel is closed to all vehicles during the winter months. Anyone wishing to visit Kamikochi during this time must walk through the tunnel.
