These are triumphant times for the Communist Party. President Xi Jinping, the general secretary, governs with seemingly unobstructed authority. The balance of power in Asia and the Pacific appears to be shifting in China’s favor. Extreme poverty, especially in rural areas, is nearing eradication.

And yet the Communist government seems intensely vulnerable at times as it confronts a slowing economy and a society in the throes of staggering change. In a country still working to find its place in the world, the party whips up nationalism as an elixir. Lately, it has gone into overdrive, inventing new forms of agitprop.

Across China this fall, the party is turning the obscure anniversary of a cherished political touchstone into a cause for passionate celebration. It has been 80 years, we are told again and again, since the end of the Long March, the 6,000-mile retreat of Communist forces that established Mao’s pre-eminence and gave the party its soul. More than 80,000 people died in the march, which began in 1934, but the bravery of the soldiers inspired generations of Chinese people to rally behind the party and its leader.

On television, Long March soap operas, documentaries and variety shows abound. Tour agencies offer packages retracing the soldiers’ routes. Students put on virtual reality goggles to relive famous battles. Joggers use a Long March-themed fitness app to measure their steps against the Red Army’s.