Sogi Power Plant
Standing at a national crossroads in technological development

Early Power

Today, Japan is one of the world’s leading countries in advanced technologies.

However, achieving this renown took several steps. As the Edo period transitioned into the Meiji period, Japan was quickly developing a wide range of technological innovations including ship building and ports, mines, steel works, machine factories, and power plants. In order to maintain their advancing industrial revolution, electricity was a necessity.

At this time, power was primarily generated through coal-fed thermal power plants. As the demand for electricity increased, coal transportation became less feasible. The answer for more power lay in hydropower.

The earliest hydroelectric power plants produced comparatively low wattage, limiting their use to local businesses. By the time the Sogi Power Plant was built in 1907, small-scaled hydroelectric power plants had been used throughout Japan. The challenge to overcome then became the ability to generate power on a national scale. 1911 marks the technological transition from these low-voltage plants, like Sogi, to large-scale capacity and the building of dams to support this larger demand such as the Shimotaki Power Plant that supplied power to Tokyo in 1912.

How it Works

The water used to power the Sogi plant came from less than a mile upriver from the Sogi-no-Taki waterfalls. The impressive waterfall we see today flows over a redesigned and constructed waterfall to help protect the area from flooding. Constructed between 2007 and 2012, this newly designed landscape offers peaceful views and walks along the river.

During the Meiji period, when the Sogi Power Plant was built in 1907, water from the original waterfall was diverted to feed the power plant.

Once the water reached the ridge above the power plant, the water was directed down a steep hill to garner enough force to push the blades of the turbines of four generators inside the building. As water pushed the blades, a rotor above lined with magnets spun.

Along the interior of the outer casing for the rotor was a configuration of copper wires. The action of the spinning magnets along the copper wires produces electricity. This simple idea has evolved into more complex types of power plants, most notably through the use of dams which uses pressure and gravity to force the water to spin the blades faster.

The Sogi Power Plant had four turbines which produced more than enough electricity for the nearby Ushio gold mines. With the excess power, the founder of the Sogi Power Plant, Shitagau Noguchi, was able to power a calcium carbide manufacturing company in Kumamoto Prefecture to the north.

Cultural Change

In the early 1800s, Japan’s Edo period, which had ruled Japan since 1603, was beginning to decline. Although the Edo period is celebrated for its rich art, literature, and theater, the ruling Shogunate maintained an isolationist foreign policy and a strict social structure within a feudal government.

The decline of the Edo period witnessed a succession of civil wars between feudal states and the Shogunate capital, Edo, now modern Tokyo. In 1868, the Shogunate surrendered and restored power to the Emperor who took the name Meiji, or “enlightened ruler.” In an effort to unite and strengthen Japan and in response to an increase in Western encroachment, the new Meiji government began a nationwide reformation at an unprecedented scale impacting every facet of life.

For the next 14 years Japan’s governing state underwent a radical change from traditional feudalism to a more democratic process. New governmental policies included a constitution and term limits for newly established governmental positions. The traditional feudal lords, daimyo, handed their authority to the Emperor and became governors; while the traditional daimyo estates or Han system was disbanded and replaced with Prefectures.

Embracing Cultural Change

Shitagau Noguchi, founder of the Sogi hydroelectric dam grew up during the last decade of the Edo period. Originally born in the samurai class, Noguchi was an early entrepreneur in electronic engineering at the dawn of the new Meiji period. Today, Noguchi is considered the father of electrochemical engineering in Japan.

In the late 1890s, Noguchi began working for the Japanese branch of Siemens, a German owned engineering company. It is likely through his German connections that he was able to found Sogi Denki Electric and build the Sogi hydroelectric dam. He did this with European architects and using German turbines.

The dam’s primary contract was with a nearby gold mine in Ushio. With a capacity of 800kW, the dam exceeded the mine’s needs. With his entrepreneurial mindset, Noguchi used the extra electricity to power his newly found company, Nippon Carbide Shokai, which produced calcium carbide, an essential ingredient in fertilizer.

Throughout the 1920s, Noguchi continued to expand, open, and merge new companies, quickly adopting the latest technological advancements. More specifically, Noguchi broadened new chemical developments in a range of fertilizers and established a new dam for the Chugoku region.

In the 1940s, Noguchi established a personal and business relationship with Korea. By the time of his death in 1944, Noguchi had invested his own personal fortune towards the development of Korean schools while also establishing the Noguchi Institute in Tokyo, which continues to thrive as a chemical research center.

A Submerged Power Plant

For nearly 60 years, the Sogi Power Plant continued to generate power. In 1965, a dam was built across the Sogi-no-Taki River, downstream of the Sogi Power Plant - the Tsuruda dam. The Tsuruda dam was primarily built to protect against floods but to also generate power at a larger scale. Due to the high amount of water during the rainy season, the river behind the dam floods, submerging its older counterpart. This continuous flooding has taken its toll on the long-term preservation of this power plant. Walls have collapsed over time and previous conservational efforts are visible.

The Sogi Power Plant plays an important role in Japan’s early industrial development. Together, with several other Industrial Heritage sites throughout Japan, the Sogi Power Plant is an important part of Japan’s history. To acknowledge the importance of this history, Japan is seeking to recognize these industrial sites as part of their cultural heritage.

As part of this recognition, CyArk has partnered with geopositioning manufacturer, Topcon and Japan’s National Congress of Industrial Heritage to document this unique site. For the project, we used a range of technologies including unmanned air vehicles, mobile scanning, and terrestrial scanning. The data collected will contribute to the efforts to nominate the Sogi Power Plant as a UNESCO Industrial Heritage Site.

Documenting a Cultural Transition

In December of 2014, Japan’s National Congress of Industrial Heritage, in collaboration with the Japanese government, nominated the Sogi Power Plant to the CyArk’s 500 Challenge acknowledging the importance of the Sogi Power Plant and its contribution to our shared global heritage.

As part of recognizing the role the Sogi Power Plant has played in Japan’s cultural transformation, CyArk has partnered with the geopositioning manufacturer, Topcon and Japan’s National Congress of Industrial Heritage to document this unique site. For this project, the team employed a range of new technologies including unmanned air vehicles to photograph details of the terrain, mobile scanning to document the broader environment, and terrestrial scanners to capture the details and condition of the power plant. The data captured will contribute to the on-going efforts towards monitoring and long-term conservational planning of the site.


00:30 / 01:00