Koshimizugaike Pond located in Hioki in Shintomi Town, Miyazaki Prefecture, is a pond, which is oblong in north and south and about 1 kilometer in circumference and 7 hectare in area. Having never dried up, the pond is covered with beautiful lotus flowers in summer. From the middle of July to the middle of August every year, white and pink lotus flowers come into bloom and colorfully decorate the surface of the pond.

In winter, lotus roots are harvested in the unique method that has been handed down in this area. It is said that cultivation of lotus roots started by Akizuki Taneshige, the 7th lord of the Takanabe domain, as the measures to save local farmers from food shortage in winter.

Beside the pond is Mizunuma Shrine, which is said to have been founded in the Genroku era (1688-1703). The enshrined deity, Mizuhanome no Kami, is worshipped by the local people as the goddess of agriculture and prevention of bad luck concerning water.