The vine Architects Preserving the Iya Vine Bridge every 3years.

Iya Vine Bridge（Iya-no-Kazurabashi）, one of the three strangest bridges in Japan and designated as a National Important Tangible Folk Cultural Asset, is a suspension bridge made of Japanese honeysuckle over the ""unexplored"" Iya Valley in Miyoshi City, Tokushima, Shikoku. It is 45 m long, 2 m wide, and 14 m above the water. In the old days, it was the only way to cross to the other side of the river in the deep mountain valley area. Nowadays, it is a tourist attraction, bringing around 350,000 visitors a year who come to experience the bridge crossing.

Iya Vine Bridge（Iya-no-Kazurabashi） is replaced every three years by the local Kazura Bridge Preservation Association to prevent it from deteriorating and to pass on the replacement techniques. The bridge is still built almost entirely by hand, using natural materials and traditional techniques. The material used to make the bridge, Japanese honeysuckle, used to grow wild in the mountains of Iya, but in recent years it has become difficult to obtain sufficient quantities to make the bridge.

In response, the Executive Committee for Securing Materials to Replace the Iya Kazura Bridge was set up, and the Agreement on Forestation Supporting Tree Culture and the Agreement on Securing Materials for the Iya Vine Bridge were concluded. In order to secure materials to replace the bridge, we are procuring materials from a state-owned forest in Kochi Prefecture, while in the local Iya area, we are raising Japanese honeysuckle seedlings together with elementary and junior high school students as part of their environmental education, planting them in the state-owned forest in East Iya, with the goal of procuring materials locally.

By securing traditional materials and passing on the replacement techniques, the practice of replacing the bridge once every three years has been passed on. Despite temporarily declining sharply due to the effects of COVID-19, the number of people crossing the bridge, including foreign visitors who prefer to experience the local nature and culture, remains around 350,000 per year. We've confirmed the planted 200 seedlings in the local natural forest are growing, and we are now on track to grow Japanese honeysuckle, which is said to need 20 years to reach the age it can be used for the bridge replacement, and to procure materials locally.