I am doing some research on the establishment of "Kimilsungism" and its links to the Soviet Union. Finding the connections has been very easy but a question that I can not seem to find the answer to is why Stalin removed his troops. This action is completely contrary to what the Soviets did in Eastern Europe when developing communist countries. Any insight would be appreciated, at this point it is more for my own curiosity than the paper.
Ask yourself the antithesis: why did Stalin NOT remove troops from Eastern Europe? Do those same factors occur in Korea?
The USSR wanted a few things in Europe. First, Russia and Prussia had ruled/controlled/fought over the Baltic for some time. By taking over Poland and the Baltic states, Russia was simply reasserting control over territory they had ruled before.
They were also creating a buffer zone between Europe and the USSR. The War of Polish Succession, the War of Austrian Succession, the Polish-Russian War, the War of the Second, Third, Fourth, Fifth, Sixth, and Seventh Coalitions, Napoleon, and World War 1 - all was not quiet on the western front. After losing more people than everyone else in all of World War 2 combined, the Soviets set up client states so that they could strike into Europe easier, or defend Russia proper with a thousand miles of frontier.
Asia was a different story. Historically, the only invaders from the East were the Mongols. Russia and Japan fought, but that was in Manchuria and the Japanese didn't march on Moscow - it stayed localized in the Far East. Also, if someone wanted to traipse across Asia to get to European Russia, they'd have to go through SIBERIA. Good luck with that.
While Stalin focused on Russian/Soviet communism (unlike Lenin who wanted a worldwide revolution), he was still supportive of other countries becoming communist and Korea is no exception. The USSR poured lots of money and weapons into North Korea, but there was no need for Soviet soldiers to stay for a few reasons:
Soviet interests were in Europe. Kicking the allies out of Berlin and building up satellites in Eastern Europe were critical. At the same time, American interests were in Europe. US soldiers left South Korea in 1948 as well.
Kim Il-sung and the North Korean Workers Party controlled North Korea. They had a strong infrastructure (thanks Japan!), they redistributed land to peasants (thanks Kim!), and they were actually doing a fairly decent job of running the country. Ideologically, North Korea's leadership was ideologically pure and the people supported them. Stalin did not need to develop communism in North Korea. It was already quite well developed.
Stalin had no interest in getting tied up in Asia. His interests were in Europe (as were the Americans). China was finishing up a civil war that the communists were winning. Kim was angling to conquer the south while Syngman Rhee was spoiling for a fight to conquer the north. If Soviet troops stuck around, they could be pulled into a civil war that Stalin had no interest in.
By 1948, there was no purpose to having Soviets in North Korea. The USSR had trained, armed, and supplied the North Koreans with a solid military, the KWP was a strong ally in ComIntern, China was about to become a strong ally in ComIntern, the US had left South Korea and had left them weak and under-armed, the Japanese were zero threat to the USSR, and Stalin could use those same soldiers in Europe.