Nakano Toge Tunnel

Nakanotao Tunnel: One Man's Determination to Bring Water Through a Mountain

Deep in the rural hills south of the Saijo Basin in Higashihiroshima City, Hiroshima Prefecture, lies a remarkable feat of human perseverance — the Nakanotao Tunnel (中の峠隧道, Nakanotao Zuido). This 327-meter-long irrigation tunnel was born from a single man's refusal to accept drought as fate. Beginning in 1927, a local farmer named Okita Kaichi took up a hammer and chisel and began carving through solid rock by himself, determined to bring water from the Odayama River on the other side of the mountain to the chronically dry Fukado Pond. His solitary effort eventually inspired an entire village to join in, and by 1930 the tunnel was complete. Registered as a national Tangible Cultural Property in 2000, Nakanotao Tunnel remains in active use today, quietly sustaining the farmland it was built to save nearly a century ago.

Historical Background: A Community's Long Struggle with Drought

The Kashobara district, located on the southern edge of the Saijo Basin, was developed as agricultural land during the late Edo period. Beginning around 1804 under the guidance of the Hiroshima Domain, approximately 50 hectares of rice paddies were cultivated in this area. To supply water to these fields, Fukado Pond (also historically known as Nakanotao Pond) was constructed by damming a valley — a reservoir with a capacity of roughly 160,000 tons.

However, Fukado Pond had a critical weakness: its catchment area was extremely small. Once the pond dried up, it took years to refill. The roughly 70 farming households that depended on the pond suffered repeated droughts, with devastating consequences for their rice harvests. The situation reached a crisis point in 1926 (Taisho 15 / Showa 1), when a severe drought struck the region. In that year and the following years, 35 hectares of rice paddies produced no harvest at all, while the remaining fields yielded less than half their normal crop.

Okita Kaichi: The Man Who Tunneled Through a Mountain

Okita Kaichi (1873–1939) was a resident of the Kashobara district known for his warm character and dedication to community service. In his younger years, he had traveled to the United States to study engineering techniques — an experience that would later prove invaluable.

Confronted with the devastating drought of 1926, Okita conceived a bold plan: to dig a tunnel through the rocky ridge separating the Kashobara district from the Odayama River valley to the east, creating a 1.5-kilometer water channel that would feed into Fukado Pond. The most challenging section would be approximately 327 meters of tunnel through solid rock beneath the Nakanotao Pass.

On March 25, 1927, Okita began the work alone. He built a small hut near the tunnel entrance, providing his own food with just one sho (about 1.8 liters) of rice per day from his family. Armed with only a hammer and chisel, he chanted Buddhist prayers as he slowly carved his way through the mountain. Day after day, year after year, he worked in near solitude.

Initially, the villagers were skeptical and offered no help. But as they witnessed Okita's unwavering dedication — a single man methodically chipping away at a mountain — they were deeply moved. Gradually, more and more community members joined the effort. With the collective labor of the village and a total investment of 2,700 yen (a substantial sum at the time), the tunnel was completed on August 15, 1930.

Why It Was Designated: Architectural and Historical Significance

Nakanotao Tunnel was registered as a national Tangible Cultural Property (building) on April 28, 2000. The designation recognizes several distinctive features of this structure.

The south portal of the tunnel features a reinforced concrete semi-circular arch with a span of approximately 0.7 meters. At a time when most tunnel portals in Japan were constructed using stone masonry or brick, Okita's adoption of reinforced concrete was remarkably forward-looking — this construction method would not become widespread until after World War II. This early use of concrete technology makes the tunnel architecturally significant as a pioneering example of modern engineering in rural infrastructure.

In 1943, an additional 3.8-meter reinforced concrete box-type extension was added to the south portal to prevent rock falls, further demonstrating the ongoing evolution of the structure's engineering. The completed tunnel measures 327 meters in total length, with a width of 0.9 meters and a height of 1 to 1.2 meters.

Highlights and Points of Interest

Visiting Nakanotao Tunnel offers a deeply moving experience that connects you with the spirit of rural Japanese determination and community solidarity. The south portal, with its concrete arch framed by lush vegetation, stands as a quiet monument to one man's extraordinary willpower. Water still flows steadily through the tunnel, just as it has for nearly a century, feeding into Fukado Pond and sustaining the rice paddies of the Kashobara district.

Near the tunnel entrance, an information board installed by the Higashihiroshima Board of Education tells the story of Okita Kaichi and the tunnel's construction. The surrounding landscape of forested hills, small agricultural ponds, and terraced farmland offers a glimpse into the traditional rural scenery of the Saijo area. A walk along the maintenance path above the tunnel traces the route of the water channel and leads to Fukado Pond itself, where you can see the water from the tunnel flowing in.

A memorial stone honoring Okita Kaichi stands in the grounds of the nearby Inari Shrine (Inarou Shrine) in Goso, inscribed with a detailed account of his achievement. This monument was erected in 1950 by a grateful community that never forgot the man who changed their fortunes.

Surrounding Area: Saijo Sake Brewery District and Beyond

Nakanotao Tunnel is located in the Saijo area of Higashihiroshima, which is famous throughout Japan as one of the country's three great sake brewing regions, alongside Nada (Hyogo) and Fushimi (Kyoto). The Saijo Sake Brewery Street, centered around JR Saijo Station, features seven active breweries whose red-brick chimneys, white-walled warehouses, and traditional namako-style walls create a uniquely atmospheric streetscape. Many breweries offer tastings and tours, and the area hosts the popular Sake Matsuri festival every October.

Other nearby attractions include Kagamiyama Park, known for its beautiful cherry blossoms and autumn foliage; the ruins of Aki Kokubunji Temple, a nationally designated historic site; and the Mitsujō Kofun ancient burial mounds. Higashihiroshima also serves as a convenient base for exploring Hiroshima City, which is approximately 35 minutes away by JR Sanyo Main Line from Saijo Station.