When the Communist Party decided to relax the one-child policy in 2013, and subsequently changed the national family planning to two children per couple, it marked the end of a controversial and disquieting era in China’s history. Whilst adherence to the law sometimes depended on where you lived and your economic position, it has caused an unquantifiable amount of pain and suffering. Xiaoshuai Wang’s new film charts the effect on two families over several decades.

It’s the 1980s and Liyun (Yong Mei) and Yaojun (Wang Jingchun) both work in a factory, living modestly with their son Liu Xing. When Liyun gets pregnant again she is forced to abort the baby in-line with China’s one-child policy. Subsequently, a tragedy befalls the couple and they respond in the best way they can. Spanning several decades and oscilating between eras, we see how the policies of the Communist regime impact on their lives.

So Long, My Son is an epic family drama which tells the tale of millions through the travails of one couple and a group of friends. Wang’s film is audacious in scope and meticulously crafted.  It’s beautifully filmed and patiently paced but it’s the performances of the two leads which makes it so enthralling. So Long, My Son is a social drama documenting four decades of Chinese life.

So Long, My Son screens at London Film Festival on 12 and 13 October.