Sasago Railway Tunnel (Chuo Line), c. 1930.

“Sasago Tunnel in Kai Province (the longest in Japan measuring 15,246 ft.) on the Central Line, Eastern Division,” Imperial Government Railway, c. 1930. Completion of the tunnel in 1903 between Sasago-mura and Tsuruse-mura represented the pinnacle of tunnel construction in the Meiji era. A hydroelectric power plant was built near the worksite, providing power for electric locomotives, lighting and fans that contributed to more efficient and successful tunnel construction in Japan. The “Central Line”, officially named the Chuo Line, followed the course of the feudal Nakasendo between Tokyo west to Shiojiri, through the Kiso River valley southwest to Nagoya. Kai Province is today’s Yamanashi Prefecture.

“When the Sasago tunnel was completed on the Chuo line in 1903, the travel time of three hours by foot over the pass shrunk to ten minutes by train.

“… For Meiji leaders, there was no question that railroads were vital to the political unification and the building of the modern state. This conviction was fittingly symbolized by the calligraphy engraved on either end of the monumental Sasago tunnel, which served to link the mountainous Yamanashi prefecture with the Tokyo area.

“Providing the celebratory inscriptions over the tunnel entrances, like bookends to a magnum opus, were the two great statesmen of the Meiji era, Ito Hirobumi and Yamagata Aritomo. ‘To benefit through the earth,’ read Ito’s handwriting on the eastern end of the tunnel, to which Yamagata’s at the western end, equally steeped in the gospel of material progress, replied: ‘To build in Heaven’s stead.'”

– The Sound of the Whistle: Railroads and the State in Meiji Japan, by Steven J. Ericson, 1996