In the legend, Ondo-no-seto was excavated under the leadership of Taira no Kiyomori from 1164 to 1167 during the Heian period, to allow passage of trading ships for trade with China.
According to the legend, Ondo-no-seto was unearthed under Taira no Kiyomori's direction in 1164 to 1167 during the Heian period, enabling Chinese trading vessels to navigate through for commercial purposes.