Jugantar or Yugantar (Bengali: যুগান্তর Jugantor) (English meaning New Era or more literally Transition of an Epoch) was one of the two main secret revolutionary trends operating in Bengal for Indian independence. This association, like Anushilan Samiti started in the guise of suburban fitness club. Several Jugantar members were arrested, hanged, or deported for life to the Cellular Jail in Andaman. Thanks to the amnesty after World War I, most of them were released and could give a new turn to their political career, mainly: (a) by joining Deshbandhu's Swarajya or (b) the Communist Party of India; or (c) M.N. Roy's Radical Democratic Party; or (d) later Subhas Chandra Bose's Forward Bloc in the '30's.
This party was established by leaders like Aurobindo Ghosh, his brother Barin Ghosh, Bhupendranath Datta, Raja Subodh Mallik in April 1906. Barin Ghosh and Bagha Jatin were the main leaders. Along with 21 revolutionaries, they started to collect arms, explosives and manufactured bombs. The headquarters of Jugantar was located at 27 Kanai Dhar Lane, then 41 Champatola 1st Lane, Kolkata.
Some senior members of the group were sent abroad for political and military training. One of the first batches included Surendra Mohan Bose, Tarak Nath Das and Guran Ditt Kumar, who, since 1907, were extremely active among the Hindu and Sikh immigrants on the Western coast of North America. These units were to compose the future Ghadar Party. In Paris Hemchandra Kanungo alias Hem Das, along with Pandurang M. Bapat, obtained training in explosives from the Russian anarchist Nicholas Safranski. (Source: Ker, p397.) After returning to Kolkata, he joined the combined school of 'self-culture' (anushilan) and bomb factory run by Barin Ghosh at a garden house in Maniktala, a suburb of Calcutta. However, the attempted murder of Kingsford, the-then district Judge of Muzaffarpur by Khudiram Bose and Prafulla Chaki (30 April 1908) initiated a police investigation that led to the arrest of many of the revolutionaries. The prisoners were tried in the famous Alipore bomb conspiracy case in which several activists were deported for life to the Cellular Jail in Andaman.