Shiobara Onsen started when hot spring was found in Motoyu in 806.
In 1659, there was a big wave and Motoyu was covered with dirt so the gush in Motoyu was hidden, but there is a historical fact that is said it started again thanks to locals' wishes.
It is said that the origin of Yu Festival is separating the hot water of Motoyu into each region.
Koshikiyu festival is an event which people appreciate the blessing the hot spring and wish the long-lasting prosperity.
At first, at headspring of Motoyu, people hold "drawing ceremony" and draw "blessed hot water".
Then, at Shiobara Hachimangu Shrine, they hold "dedication of blessed hot water" to dedicate "blessed water".
And lastly, to hold "ceremony of dividing water" which divide "blessed water" to each region, people who wear kariginu and white clothes (traditional clothes) walk around in the hot spring city, and they hold "ceremony of dividing water".
The water is dedicated to hot spring shrine by locals or is delivered to the owners of headsprings.
Also, at the day, each facility opens for free for people who came there for one day with appreciation to blessing hot springs.