Battling The Bolsheviks
Following the takeover of Russia by the Communists, they created a special "Jewish affairs section" run by Jews known as the Yevsektsiya, which instigated anti-religious activities meant to strip orthodox Jews of their religious way of life. As Rebbe of a Russia-based Jewish movement, Schneersohn was vehemently outspoken against the atheistic Communist regime and its goal of forcibly eradicating religion throughout the land. He purposely directed his followers to set up religious schools, going against the dictates of the Marxist-Leninist "dictatorship of the proletariat".
In 1921 he established a branch of Tomchei Temimim in Warsaw.
In 1924 he was forced by the Cheka (Russian secret police) to leave Rostov due to the Yevsektsiya's slander, and settled in Leningrad. In this time he labored to strengthen Torah observance through activities involving rabbis, Torah schools for children, yeshivot, shochtim, senior Torah-instructors and the opening of mikva’ot; he established a special committee to help manual workers be able to observe Shabbat. He established Agudat Chasidei Chabad in USA and Canada.
In 1927 he established a number of yeshivot in Bukhara.
He was primarily responsible for the maintenance of the now-clandestine Habad yeshiva system, which had ten branches throughout Russia by this time. He was under continual surveillance by agents of the NKVD.
Read more about this topic: Yosef Yitzchok Schneersohn