The or , is a high variable-radius arch dam on the Kurobe River in Toyama Prefecture, Japan. The tallest dam in Japan, it supports the 335 MW Kurobe No. 4 Hydropower Plant and is owned by Kansai Electric Power Company. It was constructed between 1956 and 1963 at a cost of ¥51.3 billion yen. The project was a difficult engineering feat for the rapidly growing post–World War II Japan, and claimed the lives of 171 people. History In 1951, the Kansai Electric Power Company was formed to provide electric power for the Kansai region of Japan. Shortly after their formation, the area suffered from drought which caused power rationing. The drought, along with the rapid growth of post–World War II Japan, pushed the company to increase their generating capacity. After a series of geological and hydrological studies of the Kurobe River and Gorge, it was announced in late 1955 that the Kurobe Dam would be constructed. In July 1956, construction on the dam began. Problems quickly arose while transporting material to the construction site as only one small railway existed through the narrow gorge. Kansai decided to construct the Kanden Tunnel under Mount Akazawa that could bring supplies from Ōmachi eastward towards the construction site. The tunnel's construction proved an arduous task as a large fracture zone in the rock was encountered which took seven months to repair. In September 1959, the first concrete for the dam was placed and by October next year, the reservoir had begun to fill. The Kurobe No. 4 power station was built completely underground to protect it from common avalanches in the gorge and also for nature conservation purposes. By January 1961, two of Kurobe No. 4's Pelton turbines had begun operation at an initial capacity of 154 MW. In August 1962, the third turbine was in operation and by June 1963, the dam was complete at a final cost of ¥ 51.3 billion ($142.5 million (1963)). In 1973, a fourth turbine was installed and became operational; bringing the power station's production capacity to 335 MW. The fourth turbine cost ¥ 1.4 billion yen ($5 million (1973)). The first two turbines were manufactured by Voith and the second two by Japan's Hitachi. The dam initiated the development of Japan's first 275kV transmission system as well which allowed the transfer of electricity over greater distances. A total of 171 people died during the construction of