During the Meiji
period, the Sanyodo of the Edo
period and
earlier became
a section of National Highway
3 connecting Tokyo City and Kobe City (separating from National Highway
2 in Kyoto City); and of National Highway
4 connecting Tokyo and Nagasaki City; during the Taisho
period it was
integrated into National Highway
2 connecting Tokyo and Kagoshima City (separating from National Highway
1 in Mie Prefecture).