Yoi Domon is a historic tunnel carved into the steep cliffs along the right bank of the Ibo River in Yoi, Yamazaki-cho, Shiso City, Hyogo Prefecture. First excavated in 1903, during the Meiji period, this unusual passage has played an important role in local transportation for more than a century. Set among rugged rock formations beside the clear river, it is a distinctive sight that reveals how local residents overcame the challenges of the mountainous landscape.
Yoi Domon is situated beside sheer rock faces in an area known as Shimohoki no Kigan, meaning the unusual rock formations of Shimohoki. The steep terrain along the Ibo River was once a major obstacle for travelers trying to reach the remote mountain settlements of Shiso. The dramatic cliffs and unusual rock shapes have also made this stretch of the river a local scenic attraction, along with the area around the Ta i river crossing.
The combination of rugged stone walls, flowing water, and the narrow passage carved into the cliff creates a striking landscape. The site offers a glimpse into the relationship between the region’s natural geography and the practical needs of the people who lived there.
Before the tunnel was created, people traveled along a wooden walkway attached to the rock face. However, flooding frequently swept the walkway away, making passage dangerous and sometimes cutting off the local community. To establish a more reliable route, residents of the area began excavating a tunnel through the rock around 1903. The work took approximately two years to complete.
The tunnel was later enlarged in 1926 so that horse-drawn carts and other wheeled vehicles could pass through. Further improvements were carried out in 1968, allowing larger motor vehicles to use the passage. These successive modifications reflect the changing transportation needs of the region over the decades.
The Shiso District Gazetteer, published in 1923, describes the scenery between Tai and Yoi. It records two unusual giant rocks where the clear waters of the Ibo River wash against the foot of the mountains. Old pine trees extend their branches above the cliffs, while ferns and small pines grow across the rocky slopes. Below, the cliffs overlook a deep, blue pool in which the surrounding scenery is reflected.
The account also notes that a wooden walkway once enhanced the dramatic landscape, but that cutting a tunnel through the rock made the scenery even more remarkable. This historical description captures both the natural beauty of the area and the ingenuity involved in creating a safer route through it.
Even today, visitors can see square holes in the rock face on the opposite bank. These openings once held the projecting support beams of the old wooden walkway, providing tangible evidence of the route used before the tunnel was excavated.
During periods of heavy rain and rising water, the area could once become isolated from surrounding communities. The opening of the Yoi-Tai Tunnel, which provides an alternative route connecting the area with National Route 29 near Tai in Yamazaki-cho, helped resolve this long-standing transportation problem.
Yoi Domon is located at 1-1 Yoi, Yamazaki-cho, Shiso City, Hyogo Prefecture. By car, travel north along National Route 29 from the Yamazaki Interchange on the Chugoku Expressway for approximately 10 kilometers to reach the area.
After visiting the tunnel, travelers can stop at Shiso Yoi Onsen, a hot spring facility in the Yoi district. Combining a visit to the historic tunnel with a relaxing soak provides a pleasant way to explore this quiet part of Shiso City.
Yoi Domon is more than a passage through rock. It tells the story of a community that transformed a dangerous riverside route into a more dependable road, adapting it as transportation evolved from wooden walkways to carts and motor vehicles. The rugged cliffs, traces of the former walkway, and the historic account of the landscape make this a worthwhile stop for travelers interested in local history, engineering, and the natural scenery of Hyogo Prefecture.