Operation Rose was the East German plan to seal the Berlin border in 1961.
The operation began in the early hours of 13 August 1961. East German military and police units blocked streets, dismantled sections of transport infrastructure, and installed barbed wire between East and West Berlin. The action was planned in secrecy and carried out with Soviet backing.
The code name refers to the initial operation, not to the entire later history of the Wall. The temporary barriers were gradually replaced by increasingly sophisticated fortifications, including concrete segments, fences, patrol roads, watchtowers, and a controlled border strip.
A common mix-up is to call the plan “Operation Rosebud.” That name is not the established historical code name for the 1961 closure. Operation Rose is the specific term associated with the East German action that launched the Berlin Wall system.