Abstract
From ancient times, the roads to eastern area must pass through Shinano. As Shinano has many mountains, the roads were built crossing many passes (Misaka, Magome, Jumagari, Torii pass, etc.).
The representative Tosan road and Kiso road which have origin in the prehistoric age or Jomon and Yayoi periods were built in Heian period.
Tosan road which had steep Misaka pass was prosperous as a road in order to communicate governmental information urgently. Afterwords it declined in the end of the middle ages, because Misaka pass was extremely steep which it was hard for a horse to pass carrying a big load on his shoulder.
On the other hand, Kiso road developed as an industrial road and met the golden age in Edo period.
Today, Chuo expressway passes under Misaka pass. The progress of tunnel technology overcame the steep pass.
