On June 24, 1973 (the 24th of the fifth lunar month), Tianjin City of China and Kobe City of Japan established friendly relations. On June 24, 1973, Tianjin City of China and Kobe City of Japan formed friendly relations. Premier Zhou Enlai proposed calling this relationship a "sister city." This is the first city in China to establish friendly relations with a foreign city. Sister city work is an important channel opened up in the continuous development of China's people-to-people diplomacy. This channel has enabled the continuous development of friendly and cooperative relations between China and regions, cities, local governments, and local councils of relevant countries. This was a rally held in Tianjin City on June 24, 1973 to welcome the friendly delegation from Kobe City, Japan to visit Tianjin.