Former Yaotsu Power Plant Facilities

Former Yaotsu Power Plant Facilities

The Former Yaotsu Power Plant Facilities (旧八百津発電所施設, Kyū-Yaotsu Hatsudensho Shisetsu) on the right bank of the Kiso River in Yaotsu, Yaotsu Town, Kamo District, Gifu Prefecture, are the remains of a hydroelectric power station completed in 1911, and four of its structures are designated Important Cultural Properties (Agency for Cultural Affairs).

The Agency's detailed commentary says the plant was built for the Yaotsu hydroelectric project of the Nagoya Electric Power Company under its chief engineer, Shioya Masujiro: work began in 1907 and finished in 1911. In 1917 a small tailrace power station, which used the drop of the discharged water to generate more electricity, was added northwest of the main building.

It was the first power plant on the Kiso River system and one of the earliest in Japan to send large amounts of high-voltage power to cities (Agency for Cultural Affairs). Yaotsu Town says it ran through the Meiji, Taisho and Showa eras and closed in 1974, after 63 years, when the new Maruyama power station was completed.

How the Four Structures Fit Together

The main building of the Former Yaotsu Power Plant Facilities stands on the riverside, with the tailrace power station beside it to the northwest. The head tank, at the end of the headrace canal, sits on high ground about 200 meters to the east, and from its south side the spillway curves down the slope to the river (Agency for Cultural Affairs).

Water gathered in the tank dropped through penstocks to the generators; surplus water ran back to the river down the spillway. Followed on the ground, the four structures spell out how an early canal-type hydro plant handled its water. Each is described on its own page.

Two Designations

The Former Yaotsu Power Plant Facilities were designated in two stages. The main building and the tailrace power station, with the surrounding land, were designated an Important Cultural Property on May 1, 1998; the head tank and spillway, with the land that frames them, were added to the same designation on July 22, 2005 (Agency for Cultural Affairs). Both share designation number 02346.

Visiting

The main building opened as the Former Yaotsu Power Plant Museum in 1998, but because of weak seismic strength and the risk of walls collapsing in an earthquake, interior access has been suspended indefinitely since December 29, 2018 (Yaotsu Town). The restricted area is everything beyond the gate of the Former Yaotsu Power Plant Facilities.

No announcement of reopening had been found as of November 2026. The Yaotsu tourism association says the exterior can still be enjoyed with the seasons; parking is at the Morota Park car park, and by car the site is about 20 minutes from the Kani-Mitake interchange of the Tokai-Kanjo Expressway via Prefectural Route 83 and the Yaotsu Tunnel. Enquiries go to the Yaotsu Town Board of Education (0574-43-0390).