In September 2020 Ma Zhongjun, chief content officer with the TV and film production company Ciwen Media in Shanghai, invited him to head a project doing just that.

Digging into archival research and conducting interviews with experts and descendants of the villagers who once helped the Red Army, Liu said he had discovered about 7,000 soldiers, mostly new recruits younger than 20 years old, had died in combat at Songmaoling. Some military historians reckon that about 10,000 Red Army soldiers and officers fought in the battle.

The battle of Songmaoling is often billed as the Red Army's last fight to break out of the fifth encirclement organized by Chiang Kai-shek's Kuomintang forces, starting in August and lasting about 70 days, with the fiercest fighting between Sept 23 and 29, 1934.

At the battle's height almost all the male adults in the villages surrounding Songmaoling were mobilized. Most families donated their wooden doors, using them as stretchers for wounded soldiers, some historians say.

Despite putting up a valiant fight the Red Army suffered huge casualties, overcome by superior firepower, some of it sourced from the United States and Europe, Liu says.

"Some militias even used spears or cut bamboos into sharp-pointed poles to set traps. They did their utmost to resist attacks, sacrificing their lives to earn a bit of precious time for the Red Army's most important soldiers to retreat."

As the fiercest combat broke out on Sept 23, Mid-Autumn Festival that year, villagers brought traditional celebrations a day forward. That special wartime move continues to this day.