By 1929, Stalin had become sole leader of Russia.
He said, "We are between 50 and 100 years behind the west. We must make good this difference in 10 years or go under."
He wanted things to change in Russia quickly and so he brought up the five year plans, these were to modernise the Russian economy. He also brought up the idea of collectivisation. This was to modernise Russian agriculture.
These two things would transform Russia. Stalin had "borrowed" Trotsky's ideas, which was very ironic.
Stalin introduced the five year plans because he wanted to industrialise the Soviet Union, he felt it was matter of life or death. If his plans failed he believed the Soviet Union's enemies would crush it. He wanted rapid industrialisation; this was what Trotsky had wanted! Stalin gave the responsibility of devising the plans to GOSPLAN, the state planning bureau. The idea was that the state would decide targets for industrial production, and would use central planning and direction of the nation's resources to achieve the priorities set out in each plan
The first five year plan was launched in 1928. It was to b focused on building up heavy industry's like coal and steel. Propaganda was used to try to make the workers finish in just four years. The targets were tough but enormous increases in production were achieved. The first five year plan was a success.
The second five year plan (1933-7) concentrated on improving things like transport and production of machinery.
The third five year plan (1938-41) ran for only three and a half years before it was interrupted by war.
More and more resources were transferred into defence related industry's. When war broke out in 1941, Germany was attacking the world's second greatest industrial power. Fifteen years before, Russia had been a backward agriculture nation.
Russia would not have survived against Germany without the changes which the five year plans had brought.