The now-defunct Japan Socialist Party (1948-1955) was once the largest opposition party in Japan. Now transformed into the Social Democratic Party, its turbulent early history documents the course of socialist politics in Japan in the 1950s. This was the time when the party was at its height, but internal struggles between radicals and moderates led to its demise. The Japan Socialist Party collection includes internal documents, manuscripts, newsletters and other party publications of the 1950s. It is a great resource for this interesting period of Japanese politics.