Shinzo Hamai (浜井 信三 Hamai Shinzō, May 28, 1905 - February 26, 1968) was the first popularly elected Mayor of Hiroshima (served 1947-1955 and again 1959-1967). He created Hiroshima's image as a city of peace.
In 1931, he graduated from the Law School of Tokyo Imperial University, and in 1935 became employed by Hiroshima Municipality.
The circumstances of his rise to prominence result from the fact that following the nuclear bombing of Hiroshima, many municipal employees were killed or incapacitated, while Hamai was only slightly injured. At the time of the explosion, he was at his house located about 3.5 km from the epicenter. His house was partly damaged, but he was still able to walk. He immediately began relief work in cooperation with Japanese army authorities.
In October 1945, Shichirō Kihara was appointed the next Mayor of Hiroshima, and in December Hamai became his deputy. Following Kihara's dismissal from his duties in March 1947 by the Allied occupation authorities and the reforms conducted in Japan by General McArthur, first mayoral elections were held in Hiroshima in April 1947. In that election, Hamai ran against five other candidates, which included vice mayor Hisao Yamamoto and city council chairman Tsukasa Nitoguri. He won the election and became the first popularly elected mayor of Hiroshima.
As mayor of Hiroshima, he worked to rebuild his city as symbol for peace. As part of these efforts, he established a traditional annual speech delivered at the main memorial ceremony on August 6, known as Peace Declaration. The decision to that effect was to turn the anniversary into a festival of peace. He managed to get the support of the US occupation forces to that policy, as they hoped this would reduce criticism of the US government among the people of Hiroshima. In early 1948, several citizens' groups in Hiroshima were formed in order to convince the Japanese government to release former military land for civilian purposes, and together with Hamai decided to work for the enactment of a special legislation regarding the status of Hiroshima. To achieve that end, Hamai made numerous trips to the Japanese Diet in Tokyo along with his secretary Chimata Fujimoto and city council chairman Tsukasa Nitoguri. Following the parliamentary election of January 1949, he got the support of the ruling Liberal Party under Shigeru Yoshida for the initiative. These efforts led to the proclamation of Hiroshima as a city of peace under Japanese law. The law to that effect was passed in the Lower House on May 10, 1949, and in the Upper House to following day. In order for the law to become effective, it required approval by municipal referendum, which was held on July 7 ended with approval of the new law. The law went into effect on August 6, 1949.