Soviet union tried to secure communist control of the Berlin city council - failed
West wanted to speed up economic recovery, Soviet Union wanted to keep Germany weak to prevent future attack - refused its own zone trade with the other three.
Stalin did not want the allies inside Berlin, which was inside the soviet zone - he thought the affluent capitalist life would be on show to his side.
Western countries determined to remain in Berlin
Short term:
Western zones were receiving funds from Marshall aid to speed up recovery and established new currency in June 1945
Soviets responded with Otsmark currency.
West set up free elections - Soviets feared this would spread
June 1947 - merging into Bizonia and additionally Trizonia which Stalin saw as 'ganging up'
April 1948 - Soviet troops hold up and search road and rail traffic entering West Berlin.