Mrs Li says there was indeed a battle. "The KMT warned us that the Reds would eat the young people and bury the old," she said. "Many fled up the mountainside. But when we saw them, they told us not to be afraid, they only opposed bad people. I remember they were wearing straw shoes, with cloth wound around their shins." "The fighting started in the evening," Mrs Li said. "There were many killed on the Red Army side. The KMT set fire to the bridge-house on the other side, to try to melt the chains, and one of the chains was cut. After it was taken, the Red Army took seven days and seven nights to cross. Later, I was told that someone we had seen was Mao Zedong." Oxford University's Steve Tsang says the Chiang Kai-shek archives show the KMT chief did in fact order the senior warlord in the area to hold the crossing on pain of court martial, while his 100,000-strong Central Army tried to catch up with the Reds from the south. Some of the Sichuan warlord's forces arrived before the Reds at Luding, but their commander panicked as the Reds' main force arrived. He fled, leaving behind only a few of his notoriously opium-dazed soldiers to defend the bridge. The attempt to burn the bridge could not have amounted to much, as the timbers were soaked by rain. "The Maoist story of the battle was a lie, and a huge exaggeration but there was a battle," Tsang said.
Sun Shuyan's claim seems to rest partially on a negative finding: no eyewitnesses, though given that she could only find forty Long Marchers to interview after seventy years, that's hardly proof, really. She also cites
As Gen. Li Jukui wrote 50 years later in a memo never published until last month by author Sun Shuyan in her new book, "Long March:" "This matter was not as complicated as people made it out to be later."
Though I'm always happy to see interesting new sources enter the public realm, that sounds reasonably close to what Steve Tsang was describing above, and it may be that what Sun is "debunking" is the static Chinese Communist narrative rather than the current anglophone understanding. To be fair, I haven't seen the book: I am loath to rely too heavily on news accounts, but I also haven't seen any scholarly reviews yet.