The Iya Valley (祖谷渓谷 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 (東祖谷) or Oku-Iya (奥祖谷) 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.

Although there are several rivers that flow through the Iya Valley region, the Iya River (祖谷川Iya-kawa) is the principal one. Mount Tsurugi (剣山 Tsurugi-san), the second-highest peak on Shikoku island, is at the east end of Iya along the border with Tsurugi town.

Iya Valley was formerly divided into two villages East Iya (東祖谷山村) and West Iya (西祖谷山村), however, on March 1, 2006, both villages merged with other local towns to form Miyoshi City.

（From wiki 2010/04/13）