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 information about the number of sister city relationships (updated every month) and the trends in sister city relationships (updated every year).

CLAIR deems a "sister city relationship" valid if it fulfils all of the conditions below:

1. There is a written agreement for the sister city affiliation sighned by the heads of both local govrnments
2. Exchange is not limited to one specified field
3. Consent is received from the local Assembly for any exchange activities which are thought to require budgetary steps

Number of sister city relationships in Japan

1: Includes 5 cases of sister city relationships with more than one party on the Japanese side. These are:

• Minami-Alps City, Kai City, Chuo City and Showa Town, Yamanashi Prefecture partnered with Dujiangyan, Chengdu, Sichuan, China
• The Lake NAKAUMI, Lake SHINJI and Mt. DAISEN AREA MAYORS ASSOCIATION (Yonago City and Sakaiminato City, Tottori Prefecture; Matsue City, Izumo City and Yasugi City, Shimane Prefecture) partnered with Kerala, India
• The Sankan Kouiki Administrative Association (Kanonji City and Mitoyo City, Kagawa Prefecture) partnered with Jimo City, Qingdao, Shandong, China
• Shodo Island (Tonosho Town and Shodoshima Town, Kagawa Prefecture) partnered with Milos, Aegean Islands, Greece
• Tokunoshima Island (Tokunoshima Town, Amagi Town and Isen Town, Kagoshim Prefecture) partnered with Cheongdo-gun, Gyeongsangbuk-do, South Korea

2: The number of local governments in Japan who have sister city relationships with more than one overseas local government

The trends in sister city relationships

The graph below shows the trend in the number of sister city relationships throughout Japan.