It is known that a harsh drought, that lasted for 15 years, hit this region at the end of the 18th century.
The legend says that the drought ended only after a shrine dedicated to Zennyo Ryuo, a rain-god dragon of the Japanese mythology, was built on the island in the middle of this pond.
The rain-god was chosen because it was connected to Kobo Daishi, the founder of the Koya-san temples, who once successfully invoked him and brought rain at a contest held at the Kyoto Imperial Palace.
EXIF info:
Nikon Df
Lens: 24-70mm F/2.8G
Focal Length: 38mm
Aperture: F/6.3
Shutter Speed: 1/1000s
ISO Sensitivity: ISO 400