Retro Japan in Photos: Oldest roller dam in country in scenic canyon keeps generating power

Kamiaso Dam built in 1926 above rocky cliffs in the Hisui canyon along the Hida River in Shirakawa, Gifu Prefecture, is seen on March 17, 2021. (Mainichi/Koji Hyodo)

Kamiaso Dam built in 1926 above rocky cliffs in the Hisui canyon along the Hida River in Shirakawa, Gifu Prefecture, is seen on March 17, 2021. (Mainichi/Koji Hyodo)

A truss bridge above Kamiaso Dam built in 1926 in Shiarakawa, Gifu Prefecture, is seen on March 17, 2021. (Mainichi/Koji Hyodo)

The oldest existing rolling water gate in Japan is seen on March 17, 2021, at Kamiaso Dam built in 1926 across the Hida River in Shirakawa, Gifu Prefecture. (Mainichi/Koji Hyodo)

The walls of Kamiaso Dam's water gate towers are covered with stone tiles like a Western-style castle, as seen in this photo taken in Shirakawa, Gifu Prefecture, on March 17, 2021. (Mainichi/Koji Hyodo)

Giant gears to control rolling gates are seen in a hoisting machine room at Kamiaso Dam in Shirakawa, Gifu Prefecture, on March 17, 2021. (Mainichi/Koji Hyodo)

The oldest existing rolling water gate in Japan is seen on March 17, 2021, at Kamiaso Dam built in 1926 across the Hida River in Shirakawa, Gifu Prefecture. (Mainichi/Koji Hyodo)

The oldest existing rolling water gate in Japan is seen on March 17, 2021, at Kamiaso Dam built in 1926 across the Hida River in Shirakawa, Gifu Prefecture. (Mainichi/Koji Hyodo)

The oldest existing rolling gates in Japan are seen reserving water from the Hida River at Kamiaso Dam built in 1926 in Shirakawa, Gifu Prefecture, on March 17, 2021. (Mainichi/Koji Hyodo)

A water gate tower covered with stone plates like a Western-style castle is seen at Kamiaso Dam in Shirakawa, Gifu Prefecture, on March 17, 2021. (Mainichi/Koji Hyodo)

Water intakes are seen at Kamiaso Dam in Shirakawa, Gifu Prefecture, on March 17, 2021. (Mainichi/Koji Hyodo)

The oldest existing rolling water gate in Japan is seen on March 17, 2021, at Kamiaso Dam built in 1926 across the Hida River in Shirakawa, Gifu Prefecture. (Mainichi/Koji Hyodo)

The walls of Kamiaso Dam's water gate towers are covered with stone tiles like a Western-style castle, as seen in this photo taken in Shirakawa, Gifu Prefecture, on March 17, 2021. (Mainichi/Koji Hyodo)

Hoisting machine rooms whose exterior is painted beige are seen on the top of the water gate towers at Kamiaso Dam in Shirakawa, Gifu Prefecture, on March 17, 2021. (Mainichi/Koji Hyodo)

A water gate tower is seen at Kamiaso Dam built in 1926 across the Hida River in Shirakawa, Gifu Prefecture, on March 17, 2021. (Mainichi/Koji Hyodo)

Kamiaso Dam built in 1926 above rocky cliffs in the Hisui canyon along the Hida River in Shirakawa, Gifu Prefecture, is seen on March 17, 2021. (Mainichi/Koji Hyodo)