Mao Zedong’s most famous aphorism could well be, “Revolution is not a dinner party.” But perhaps he should have said, “Revolution is a dinner party where the main course is human flesh.” Here’s one gripping episode from Frank Dikötter’s The Tragedy of Liberation.

In April 1948, the communists advanced towards Changchun itself. Led by Lin Biao, a gaunt man who had trained at the Whampoa Military Academy, they laid siege to the city. Lin was considered one of the best battlefield commanders and a brilliant strategist. He was also ruthless. When he realised that Zheng Dongguo, the defending commander in Changchun, would not capitulate, he ordered the city to be starved into surrender. On 30 May 1948 came his command: ‘Turn Changchun into a city of death.’

Inside Changchun were some 500,000 civilians, many of them refugees who had fled the communist advance and were trapped in their journey south to Beijing after the railway lines had been cut. A hundred thousand nationalist troops were also garrisoned inside the city. Curfew was imposed almost immediately, keeping people indoors from eight at night to five in the morning. All able-bodied men were made to dig trenches. Nobody was allowed to leave. People who refused to be searched by sentries were liable to be shot on the spot. Yet an air of goodwill still prevailed in the first weeks of the siege, as emergency supplies were dropped by air. Some of the well-to-do even established a Changchun Mobilisation Committee, supplying sweets and cigarettes, comforting the wounded and setting up tea stalls for the men.

But soon the situation deteriorated. Changchun became an isolated island, beleaguered by 200,000 communist troops who dug tunnel defences and cut off the underground water supply to the city. Two dozen anti-aircraft guns and heavy artillery bombarded the city all day long, concentrating their fire on government buildings. The nationalists built three defensive lines of pillboxes around Changchun. Between the nationalists and the communists lay a vast no man’s land soon taken over by bandits.

On 12 June 1948 Chiang Kai-shek cabled an order reversing the ban on people leaving the city. Even without enemy fire, his planes could not possibly parachute in enough supplies to meet the needs of an entire city. But the anti-aircraft artillery of the communists forced them to fly at an altitude of 3,000 metres. Many of the airdrops landed outside the area controlled by the nationalists. In order to prevent a famine, the national­ists encouraged the populace to head for the countryside. Once they had left they were not allowed back, as they could not be fed…

Few ever made it past the communist lines. Lin Biao had placed a sentry every 50 metres along barbed wire and trenches 4 metres deep. Every exit was blocked. He reported back to Mao: ‘We don’t allow the refugees to leave and exhort them to turn back. This method was very effective in the beginning, but later the famine got worse, and starving civilians would leave the city in droves at all times of day and night, and after we turned them down they started gathering in the area between our troops and the enemy.’