Re-wording this so that hopefully I am not breaking rule #2, as a similar post was deleted earlier.
I would like some insight form some folks who are more knowledgeable on this topic than I who have access to non-biased sources that can comment further on the extent to which the Long March can be considered a success from a military point of view, perhaps drawing on other parallels in military history.
From my understanding, it seems as if the Long March was not really a success from a military point of view, even if the Communist leadership was able to escape encirclement by the KMT, based on the extent of the loss of forces and territory and the inability to gain meaningful ground against the KMT as a result of the maneuver.
With this in mind, is the idea of the Long March being a great strategic retreat essentially propaganda from the CPC? To what extent do objective observers consider the Long March the key to eventual Communist victory in the Chinese Civil War?
The Long March's main consequence was that it made Mao the center of the CCP. Prior to the march, Mao was fierce rivals with another CCP leader, Zhang Guotao, who commanded a large CCP army. Chiang Kai-Shek's troops ended up destroying Zhang's army while Mao's forces managed to escape, thus ensuring that Mao, with the command of the last formations, would be the undisputed leader.
Had Mao decided not to escape, his forces would undoubtedly have been totally destroyed. Chiang's new National Revolutionary Army, with increasing German support, had thrashed the Communist troops in the latest encirclement campaign, which was in no small part due to Mao's attempt to face them in open battle.
However, Chiang was unable to (for both military and political reasons) completely wipe out the Communists. As a result, they were able to spend the next 10 years building up their strength in Yan'an (with Soviet support) while the Nationalists exhausted themselves in a total war against the Japanese.
Think of it being like a seed. Mao's Long March got the seed to fertile soil. With 10 years of peace and quiet, soil and water, the seed grows into a large plant. What is a bigger contributor to the plant's size-the seed's relocation, or 10 years of undisturbed growth?