Hananukigawa No. 1 Power Station No. 3 Waterway Bridge

Megane Bridge: A Century-Old Aqueduct Still Powering Ibaraki

Deep in the forested mountains of Takahagi City, Ibaraki Prefecture, a graceful double-arch bridge spans a steep valley, carrying water just as it has done since 1918. This is the Hanakigawa First Power Station No. 3 Aqueduct Bridge, affectionately known as "Megane Bridge" — the "Spectacles Bridge" — for the way its twin arches resemble a pair of eyeglasses. Designated as a Registered Tangible Cultural Property of Japan and recognized as a Heritage of Civil Engineering by the Japan Society of Civil Engineers (JSCE), this remarkable structure is a living testament to early 20th-century Japanese engineering ingenuity.

History: From Coal to Waterpower in the Taisho Era

The story of Megane Bridge begins with Taga Electric Company (Taga Denki Kabushiki Gaisha), established in 1912 in what is now Takahagi City. Initially relying on coal-fired thermal power to bring electric light to the region, the company soon sought to expand by harnessing the energy of the Hanakigawa River, a 16-kilometer stream flowing through the mountainous terrain of northern Ibaraki.

In 1918 (Taisho 7), the Hanakigawa First Power Station was completed, drawing water from an intake at Torisone in the upper reaches of the river. To deliver the water to the power station, engineers needed to channel it across 2.2 kilometers of mountainside — boring tunnels through rock and bridging valleys along the way. The most spectacular section of this conduit is the No. 3 Aqueduct Bridge, constructed by Kajima Corporation (then Kajima-gumi) to carry the water channel across the Namariza Valley.

Engineering and Design: An Early Masterpiece in Reinforced Concrete

The bridge is a reinforced-concrete double-arch structure rising approximately 22 meters above the valley floor. Its piers are built from locally quarried stone, stacked to a height of about 15 meters, upon which the concrete arches spring outward to connect with the mountainside on each bank. The total length of the bridge is approximately 77 meters, with a water channel roughly 2 meters wide and 1.5 meters deep running across the top.

One notable feature of the design is the separation between the stone piers and the concrete superstructure. This was an intentional engineering decision: if the upper portion were ever damaged by a natural disaster, the sturdy stone piers would remain intact, allowing a temporary water channel to be quickly installed while repairs were carried out. This practical foresight has served the bridge well through more than a century of operation.

The spandrel sections of the arches feature vertical concrete members that echo the form of traditional wooden bridge trestle construction. Experts have noted that these elements reflect the earliest period of reinforced concrete adoption in Japanese bridge engineering, making Megane Bridge a valuable record of how the country transitioned from timber to modern materials in civil infrastructure.

Cultural Property Designation: Why Megane Bridge Matters

In 1999, Megane Bridge was registered as a national Registered Tangible Cultural Property (Building) by the Japanese government. The designation recognizes both its historical significance as an early example of reinforced concrete bridge construction in Japan and its continued function as a working piece of infrastructure.

In 2012, the Japan Society of Civil Engineers further honored the bridge by certifying it as a Heritage of Civil Engineering (Sensho Doboku Isan). This recognition highlights the bridge's importance not only as a cultural artifact but also as a landmark in the history of Japanese civil engineering and modernization.

The bridge is owned and maintained by Tokyo Hatsuden Co., Ltd. (Tokyo Power Generation), which operates a network of small-scale hydroelectric power stations across Ibaraki Prefecture. The company also manages the nearby Ishioka First Power Station — one of the oldest surviving reinforced-concrete power stations in Japan and a nationally designated Important Cultural Property. Together, these facilities paint a rich picture of the Taisho-era electrification of rural Japan.

Highlights and Visitor Experience

Megane Bridge offers a uniquely contemplative experience quite different from the grand temples and shrines that many visitors associate with Japanese cultural heritage. Standing before the bridge, you can watch water still flowing through the century-old channel — a living connection to the Taisho era that is rare among heritage structures anywhere in the world.

The bridge is set within the Hanazono-Hananuki Prefectural Natural Park, surrounded by dense forests of deciduous trees. In spring and summer, the bridge appears to float among layers of vibrant green foliage, while in autumn the valley transforms into a tapestry of red, gold, and orange as the maples and oaks change color. The sound of the mountain stream below and birdsong overhead create a profoundly peaceful atmosphere.

Photography enthusiasts will find the bridge particularly rewarding. The interplay of the geometric arches against the organic forms of the surrounding forest offers compositions that change dramatically with the seasons and time of day. Early morning visits, when mist often lingers in the valley, can produce especially atmospheric images.

Nearby Attractions: Hananuki Gorge and Beyond

Megane Bridge is located near the famous Hananuki Gorge (Hananuki Keikoku), one of Ibaraki Prefecture's most beloved scenic spots. The gorge stretches along the Hanakigawa River and features several notable sights.

• Shiomidaki Suspension Bridge — A 60-meter-long pedestrian suspension bridge offering panoramic views of the gorge and Shiomi Waterfall below. During autumn, overhanging branches create a vivid canopy of crimson and gold leaves.
• Namerigafuchi — A mysterious deep pool in the river surrounded by legend and folklore, set amid the natural beauty of the gorge.
• Fudo Waterfall and Otome Waterfall — Two waterfalls accessible from the Hananuki parking area, offering refreshing scenery in summer and stunning colors in autumn.
• Hananuki Gorge Autumn Festival — Held annually throughout November, the festival features local food stalls, souvenir shops, and evening illumination of the foliage around the suspension bridge.
• Mount Tsuchidake — A 600-meter peak near the gorge with a summit observation deck offering 360-degree panoramas. On clear winter mornings, Mount Fuji is visible from the top.

For visitors interested in industrial heritage, the broader region around Takahagi City and neighboring Kitaibaraki City features additional historic power station facilities operated by Tokyo Hatsuden, including the nationally designated Important Cultural Property Ishioka First Power Station.

Best Times to Visit

Megane Bridge can be enjoyed year-round, but each season offers a distinct character. Fresh green foliage in late April through May provides a lush backdrop. Summer brings deep shade and cool breezes along the valley. The most popular season is autumn — mid-November to late November — when the surrounding forest blazes with color. Winter offers stark, quiet beauty with bare branches revealing the bridge's full architectural form against the sky.