speaking to youth about surviving the atomic bombing of Nagasaki at a UN event in
Vienna in 2007 Nihon Hidankyo is a nation-wide organisation formed by survivor groups of atomic bomb victims from
Hiroshima and Nagasaki in each
prefecture. The fallout from
Castle Bravo, a thermonuclear weapon test conducted at
Bikini Atoll by the United States in 1954, caused acute radiation syndrome in residents of neighbouring atolls and 23 crew members of the Japanese fishing vessel
Daigo Fukuryū Maru. This led to the formation of the
Japan Council against Atomic and Hydrogen Bombs in Hiroshima the following year. Inspired and supported by this movement, atomic bomb survivors established Nihon Hidankyo on 10 August 1956, at the second annual conference of the council in Nagasaki. , Shigemitsu Tanaka, and Toshiyuki Mimaki at the
2024 Nobel Peace Prize Ceremony with
Jørgen Watne Frydnes However, the movement's solidarity was jeopardised when the council became actively involved in the
anti-U.S.-Japan Security Treaty movement alongside the left-leaning
Japan Socialist Party in 1959. A large number of supporters withdrew from the council, and with the support of the conservative
Liberal Democrats, a new organisation, led by Masatoshi Matsushita, leader of the staunchly anti-communist
Democratic Socialist Party, was established. In 1961, when the
Soviet Union resumed nuclear tests, the communist wing of the council refused to denounce them, which led to severe internal tension. This led to a further split in the movement, with a Japan Socialist Party-backed group that denounces nuclear tests by any nation breaking away as a new council. These tensions within
anti-nuclear movements caused some prefectural Hidankyos to split at the local level as well, such as in Hiroshima, where there are both Socialist Party-backed and Communist Party-backed Hidankyos with the same name. The nationwide organisation itself decided not to align with any political movements in 1965, after they became highly politicised. == Activities ==