 The following year, the Soviets began taking measures to control Korean population movement to their territory; however, they were not completely successful until 1931; after that date, they halted all migration from Korea and required existing migrants to naturalise as Soviet citizens.The Soviet policy of "korenizatsiya" (indigenisation) resulted in the creation of 105 Korean village soviets (councils) in mixed-nationality "raion", as well as an entire "raion" for the Korean nationality, the Pos'et Korean National Raion; these conducted their activities entirely in the Korean language.The Soviet Koreans had a large number of their own official institutions, including 380 Korean schools, two teachers' colleges, one pedagogical school, three hospitals, a theatre, six journals, and seven newspapers (the largest of which, "Vanguard", had a circulation of 10,000).