On June 18, 1948, the first ¡°Berlin crisis¡± broke out. On June 18, 1948, the United States and France issued the ¡°Decree on the Reform of the Colonial Monetary System¡±; on June 21, the Western reform was officially implemented in the Occupied Zone, and the ¡°B¡± Mark was issued in the West Berlin. On the following day, the two currencies circulated simultaneously in the Great Berlin, causing chaos; on June 22, the USSR announced that it would implement monetary reforms in the Eastern Berlin and the entire Great Berlin, and issued the ¡°D¡± German Mark. On June 23, the Soviet Union stopped transportation between the West and the upper West of Berlin with the need for coal and steel, and stopped the supply of coal to the West Berlin, after the first air lock to occupy the South Berlin crisis zone.