CLAIR collects information about all sister city relationships in Japan through prefectural governments and designated cities (local governments that are not designated cities will submit through their prefectural government). Here you can find a list of all sister city relationships in Japan (updated every month).

• Sister cities in Japan by Prefecture
  Click on the Prefecture name to see a list of sister city relationships within that Prefecture
• Sister cities in Japan by Country and Territory
  Click on the country name to see a list of sister city relationships within that country