In Japanese the ways or the roads are transcribed in the kanji -letter 道 ( pronounciation : Do ) or 路 ( pronounciation : Ji ) . Kaido means the road with many towns in general. And main official roads in history.
Nakasendo is made from three parts, i.e. Naka, sen,and do. Naka means midland or inland, Sen means mountains. Therefore Nakasendo
means the inland road running through mountains.
Then the Kaido-road through Kiso area is named Kiso-kaido or Kiso-ji, for examples. But Tokaido is made from two parts, i.e. Tokai and do.
It means the road which goes through Tokai area, the area along the coast of the Pacific Ocean from Nagoya to Shizuoka.
Hokkoku-kaido means the road running towards / through northern coutries (provinces),
e.g. Wakasa, Kaga, Noto, Echizen, Etchu, Echigo ― now ,Fukui pref., Ishikawa pref., Toyama pref., and Niigata pref. ―. Hokkoku means the countries located north than Kyoto. In old Japan Kyoto was the center point, by which each place-position was measured geographically
or geopolitically.
On the other hand, Koshu-kaido means the road running through Koshu, now Yamanashi pref..