Usuidai Sankyoryo (Megane Bridge)

Usui Third Bridge is located in Sakamoto, Matsuida-cho, Annaka City, Gunma Prefecture, and is one of Japan’s largest brick-built four-arch bridges spanning the Usui Pass. Because of its graceful appearance, it is commonly called the “Eyeglass Bridge,” and it is now designated as an Important Cultural Property of Japan. Construction began in June 1891 and was completed in December 1892. Built in just one and a half years, the bridge was a grand structure that brought together the most advanced civil engineering technology of its time, measuring approximately 91 meters in length and 31 meters in height. About 2 million bricks were used, and the design was carried out by British engineer Charles A. Pownall and Japanese engineer Seiichi Furukawa. It is a structure that symbolizes the introduction of Western technology during the Meiji era.

This bridge was built as an essential structure supporting the Abt system railway, which was introduced for the first time in Japan to cross the Usui Pass, once known as a “difficult transportation route.” The Abt system is a method that uses a rack rail with gear-like teeth installed between the rails to allow trains to travel safely on steep gradients. It was used on the Shinetsu Main Line between Yokokawa and Karuizawa for about 70 years, from 1893 until the opening of the new line in 1963.

Today, Usui Third Bridge, along with the Second through Sixth Bridges and related tunnels and the remains of a substation, is designated as an Important Cultural Property of Japan under the name “Usui Pass Railway Facilities.” The former railway line has been developed into a walking trail called the “Abt Road,” where visitors can walk across the bridge and, along the way, view historical railway remains such as the former Maruyama Substation and the ten tunnels up close.

The area around the Eyeglass Bridge is surrounded by nature that changes with the seasons, offering different kinds of beauty in spring’s fresh greenery, summer’s deep green, autumn’s brilliant foliage, and winter’s snowy scenery. In particular, during the autumn foliage season, the sight of the red-brick arches framed by colorful leaves is spectacular, making it a popular photo spot visited by many tourists.

Usui Third Bridge is a valuable heritage site that symbolizes Japan’s modernization, blending the engineering prowess and aesthetic sensibility of the Meiji era. It has also been selected as one of the Ministry of Economy, Trade and Industry’s “Modern Industrial Heritage Sites,” by Hiroshi Matsumura as one of Japan’s 100 Famous Bridges, and as one of the “Heritage 100 Selections.” As a symbol of the Usui Pass where history, culture, and nature harmonize, it continues to be cherished by many people today.