Hakusui Dam, Oita

Hakusui Dam, located on the upper reaches of the Ono River in Taketa City, Oita Prefecture, stands as one of Japan's most aesthetically striking hydraulic structures. Commonly referred to as "Japan's most beautiful dam," it was designated as a National Important Cultural Property in 1999 as a representation of the country's agricultural modernization. Construction began in 1934 under the direction of civil engineer Yasuo Ono and was completed in 1938, addressing long-standing irrigation challenges faced by farmers in the region.

The dam measures 14 meters high and just under 90 meters wide, making it considerably smaller than typical hydroelectric dams. It is a stone masonry-based gravity dam built specifically for agricultural water usage. The structure's distinctive design features stepped and curved spillways at each end, engineered to control water velocity and prevent erosion of the fragile volcanic ground characteristic of the Aso mountain area. As water flows over the center of the structure, it appears white—hence the name Hakusui, meaning "white water".

Visitors experience the dam's cascading waters from two distinct vantage points. The left bank offers views from below, where the stepped spillway creates a mesmerizing curtain-like effect of white foam descending the structure. The right bank provides an elevated perspective overlooking the surrounding landscape. Visitors cannot cross the dam itself, and traveling by car between the two sides requires significant time, so advance planning is recommended. The seasonal changes enhance the visual appeal, with the dam's water surface reflecting spring cherry blossoms, summer greenery, autumn foliage, and winter snow.

The dam is approximately 30 minutes by car from central Taketa and cannot be reached by public transportation. Free parking lots with restroom facilities are available on both sides. From the left bank parking area, the dam is approximately a 3-minute walk, while the right bank requires about a 1-kilometer walk. The site is free to enter. Water flow visibility depends on water levels and seasonal conditions, so checking current conditions before visiting is advisable.