The Iya Valley (Iya Keikoku) region in Tokushima Prefecture, Japan is a scenic area known for its dramatic mountain valleys and old vine bridges. Although access has improved in recent years, the Iya Valley and the inner parts of Shikoku have historically been remote and difficult to enter, making them a favorite retreat for refugees and defeated warriors. Most notably, members of the Taira clan were rumored to have entered the area after losing the Genpei War to the Minamoto clan in the late 12th century.
In modern times, the Iya Valley has become an increasingly popular tourist destination. Although the west part of the valley area has good road access and other tourist facilities, the eastern area known as East Iya or Oku-Iya is still relatively difficult to access and thus the natural beauty is largely undisturbed. Several vine bridges, once the only method for crossing the rivers, continue to span the valleys and have become a popular tourist attraction. To increase safety, many of these bridges have been reinforced with steel or wire frames. White water rafting is also a popular activity.