Sanbe Volcano that has nurtured
a bountiful way of life

A lake formed by an eruption

Ukinunonoike Pond

Mt. Osanbe and Mt. Kosanbe rise above the serene water of Ukinunonoike Pond. On days when there is no wind, a mirror image of the mountains (called “Sakasa Sanbe”) is reflected on the surface of the lake. This pond that lies in the lower part of Nishinohara is a natural lake with an area of about 13.5 ha. The lake was formed by volcanic ejecta from Sanbe Volcano blocking the exit of the valley, and it is the source of the Shizuma River that flows into the plains of Oda City. The lake is also important as a water source for irrigating fields, and the Nibehime Shrine on the shore of the lake is a place of worship for the farmers of the basin. Only a small amount of water flows into the lake, and most of the water seems to be supplied by spring water percolating up from the bottom of the lake.
The name is said to derive from an old legend about a giant serpent and a young woman, in which the clothes of the young woman who entered the water floated on the surface of the lake. It is also one of the possible sites of the “Ukinuma Pond” mentioned in the Manyo poem by Kakinomoto no Hitomaro.

1Dam lake: With Nishinohara at the top and a large amount of volcanic ejecta deposited in the valley of the Shizuma River, the Ukinunonoike Pond has been formed from the dam created by the sediment. There is also a legend that during the Hakuho earthquake that occurred in 684, Mt. Sanbe collapsed and the earth and sand that flowed down created a dam that formed the pond. Further collapsing of the mountain after the volcanic activity may also have affected the expansion of the pond.
2The Manyo poem of Kakinomoto no Hitomaro: Poem No. 1249 in Volume 7 of the Manyoshu anthology reads, “As I pluck for you a water chestnut from Ukinuma Pond, my dyed sleeves become wet.” The poet Kakinomoto no Hitomaro was deeply connected with Iwami, and it is thought that Ukinunonoike Pond may well be the Ukinuma Pond he wrote of.