12-05-2025
Aqueduct Helped Electrify Tokyo in Meiji Era; Historic Brick Structure Still Carries Water
The Yomiuri Shimbun
The Ochiai Aqueduct
OTSUKI, Yamanashi — After getting off a train at Otsuki Station in Yamanashi Prefecture, I traveled south along the river on National Route 139 for about five kilometers, into the neighboring city of Tsuru, when a large brick structure came into view on my left.
The Yomiuri Shimbun
The Komabashi hydropower station
It was the Ochiai Aqueduct, built in 1906, part of a 6.7-kilometer waterway that takes water from the Katsura River and carries it to be used at the Komabashi hydropower station, which today belongs to TEPCO Renewable Power, Inc.
The aqueduct is 56 meters long and 8.5 meters wide. I left the road and entered a small path. When I beheld the aqueduct, which still carries water, I was overwhelmed by its majestic appearance, reminiscent of a huge red wall. You can even walk under its supporting arches.
The Yomiuri Shimbun
Water falls about 100 meters through these two hydraulic pipes and turns the turbine.
Tokyo Dento Kabushiki Kaisha, the predecessor of today's Tokyo Electric Power Company Holdings, began operating the hydropower station on Dec. 20, 1907. On that day, it turned a current of water flowing from Mt. Fuji into a current of electricity flowing toward Tokyo. Via the Waseda substation, about 76 kilometers away, the electricity reached the Azabu and Kojimachi areas at 4 p.m. on the day. This was the beginning of Japan's first long-distance power transmission system.
In the following year, the plant started to send electricity to other parts of Tokyo: Kanda, Nihonbashi, Asakusa, Fukagawa, Kyobashi, Shitaya and Honjo. As people's lifestyles changed in the Taisho (1912-1926) and Showa (1926-1989) eras, the power station played a pioneering role in supplying electricity from rural areas where it was produced, to urban areas where it was consumed.
The power station is still in use nearly 120 years later, but currently undergoing reconstruction.
The Yomiuri Shimbun
A turbine is on display at the power station.
Two thick hydraulic pipes run down the slope to a turbine in the basement of the power plant. The exterior of the facility shows few traces of its original form. The building with a brown peaked roof still has its original brick walls, but they have been painted and the brickwork is not visible from a distance. A small portion of the earth-colored brick foundation remains behind the building, near the water outlet.
Local schoolchildren sometimes visit the site, and many express surprise at learning that such a facility exists.
'I hope local residents learn more about the power station's history,' said the general group manager of the power station.
Komabashi hydropower station
The Yomiuri Shimbun
Address: The power station: 3-5-8, Komahashi, Otsuki, Yamanashi Prefecture; The aqueduct: 233, Igura, Tsuru, Yamanashi Prefecture.
Access: The nearest train station to the hydropower plant is Saruhashi Station on the JR Chuo Line. The power station is not open to the public. To reach the aqueduct, walk about 15 minutes on National Route 139 from Kasei Station on the Fujikyu Railway toward Otsuki, cross the Ochiai Bridge and turn right and walk for about five more minutes.
