The Long March took place from October 1934 - October 1935. It meant that communism was not completely wiped out by the Kuomintang, that the people of China learnt about communism and supported the communists, that the Kuomintang got control of the south of china and most of the communists died from illness, exposure and Kuomintang attacks.
At the time it was significant because otherwise all the communists would have been annihilated. Its effects were not seen immediately but in the short term still it allowed the communist army to gather their strength and troops and meant that when they tried to take back the country the ordinary people of China knew about communism and its benefits and would support them over the Kuomintang. This also meant that when the Japanese invaded in 1936 they were strong enough and had enough support to fight and defeat them.
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