On the eve of the Long March of the Central Red Army in October 1934, Chen Yun was appointed as the central representative of the Fifth Army of the Red Army, responsible for dealing with various urgent problems. At the beginning of the Long March, Chen Yun took the lead in rectifying the morale of the troops and led the troops to fight for six days and six nights. Just after the Red Army broke through the enemy's third blockade line, the unprecedented fierce Battle of the Xiang River began. At the moment of life and death, his "100,000 Fire Letters" guaranteed the smooth crossing of the river by the Red Thirteenth Division.
In early 1935, Chen Yun led a team into Zunyi, and then attended the Zunyi Conference as a member of the Politburo and a member of the Standing Committee of the Central Committee, voting for Mao Zedong at a critical moment, and the mysterious precious manuscript was also from his hand. Later, in the Qiaodu Jinsha River, Chen Yun made important contributions.
During the Long March, Chen Yun was ordered to "disappear" from the ranks to complete another arduous mission. Since then, he has spared no effort to publicize the Long March through various forms, becoming the first person to publicize the Long March to the world.