In the 18th Century, Zenkai, a monk at Rakan-ji temple, witnessed a person falling into the waters of the Yamakuni River in Yabakei from the dangerous, cliff-hugging path it was necessary to negotiate to reach his temple. Perhaps in atonement for his criminal years while a youth, Zenkai laboured single-handedly for the next 30 years chiselling away rock creating a 342m-long tunnel for safe passage. A fee was levied to pass through the tunnel making the Ao-no-Domon Japan’s first toll road. In later times the tunnel was widen to take modern traffic.