The Soviet Union did not directly pursue manned space flight. All development efforts had a military objective. The R-7 booster was developed as an ICBM. A surveillance satellite, the Zenit was built, again with a military objective. To the casual observer, the exteriors of Vostok ("east") and Zenit appeared much the same.
The Vostok was the first manned spacecraft. It was not maneuverable and could only hold a single occupant. It also landed so forcefully that the occupant had to eject before landing and came down by parachute. The R-7 was used as the launch vehicle for the Vostok flights.
More missions were planned, but a change to the improved Voskhod caused Vostok 7 thru Vostok 13 to be cancelled.
The cancelled flights:
Vostok 7, April 1964, Komarov
Vostok 8, June 1964, Belyayev
Vostok 9, August 1964, Volynov
Vostok 10, April 1965, Beregovoi
Vostok 11, June 1965, Leonov
Vostok 12, August 1965, Khrunov
Vostok 13, April 1966, Gorbatko