The Experimental Design Bureau (Russian: Опытное конструкторское бюро, Opytnoe konstruktorskoe bûro; ОКБ), commonly known as sharashka (Russian: шара́жка, [ʂɐˈraʂkə]; sometimes sharaga, sharazhka) was an informal name for secret research and development laboratories in the Soviet Gulag labor camp system. Etymologically, the word sharashka is derived from a Russian slang expression sharashkina kontora ("Sharashka's office", which in its turn comes from the criminal argot term sharaga (шарага) for a band of thieves, hoodlums, etc.), an ironic, derogatory term to denote a poorly organized, impromptu, or bluffing organization.
The scientists and engineers at a sharashka were prisoners picked from various camps and prisons and assigned to work on scientific and technological problems for the state. Living conditions were usually much better than in an average taiga camp, mostly because of the absence of hard labor.
The results of the research in sharashkas were usually published under the names of prominent Soviet scientists without credit given to the real authors, whose names frequently have been forgotten. Some of the brilliant scientists and engineers imprisoned in sharashkas were released during and after World War II, continuing independent careers and becoming world-famous.
In 1930 Leonid Ramzin and other engineers sentenced in the Industrial Party Trial were formed into a special design bureau under State Political Directorate (GPU), which was then the Soviet secret police.
In 1938, Lavrenty Beria, a senior NKVD official, created the Department of Special Design Bureaus at the NKVD USSR (Отдел особых конструкторских бюро НКВД СССР). In 1939, the unit was renamed the Special Technical Bureau at the NKVD USSR (Особое техническое бюро НКВД СССР) and placed under the leadership of General Valentin Kravchenko, under Beria's immediate supervision. In 1941 it received a secret name, the 4th Special Department of the NKVD USSR (4-й спецотдел НКВД СССР).