Yasaka Dam is located 14 km above the estuary of the Oze River, on the border of the Hiroshima and Yamaguchi Prefectures, Japan. Yasaka is a 120m high gravity type concrete dam and was built to provide multiple benefits, including the provision of drinking water, downstream flow regulation, flood mitigation and hydropower. Construction commenced in 1982 and the dam was completed in 1990.

In contrast to many hydro dams, Yasaka is in close proximity to a relatively large population base, including Iwakuni (pop 110,000), Ootake (32,000), Waki (7000) and Miwa (5000). The dam environment is essentially suburban, being about one hour drive from central Hiroshima (population of 1,110,000).