Jung Chang was born in China in 1952 and came to Britain in 1978. She is the author of Wild Swans, Mao: The Unknown Story (with her husband, the historian Jon Halliday) and Empress Dowager Cixi: The Concubine Who Launched Modern China. Her books have been translated into more than 40 languages and sold more than 15m copies outside mainland China, where they are banned. Her latest, Big Sister, Little Sister, Red Sister: Three Women at the Heart of Twentieth-Century China, charts the lives of the Soong sisters, who were among the most significant political figures of early 20th-century China.

Your new book explores the dynamic between three women in a family, as did Wild Swans…

Wild Swans shows how life was different for each of the women – my grandmother, my mother, me. This book is also about very different lives, but because of political beliefs not generations. Big Sister [Soong Ai-ling] and Little Sister [Soong Mei-ling] were passionately anti-communist, whereas Red Sister [Soong Ching-ling] supported Mao. To start with, I didn’t want to write about the sisters; they were like fairytale [characters]. But while I was doing research, I realised how extraordinary they were, with all their mental agonies, moral dilemmas and heartbreaks.

Did you aim to show how the political is personal?

Yes – the sisters’ personal lives were more intimately connected with politics even than in Wild Swans. These women were right at the centre of Chinese politics – Ching‑ling was married to the father of the Republic of China, Sun Yat-sen. Two of the three sisters miscarried and could never conceive again. Their miscarriages were a direct result of Chinese politics. Of the three sisters, there is just one descendant, living in Texas, who is the son of Ai-ling’s youngest son [Ling C Kung] and Hollywood star Debra Paget, who was Elvis’s lead lady in Love Me Tender.

The book is dedicated to your mother…

My mother inspired me to write Wild Swans and she’s been so supportive of all my work. She lived under Chiang Kai-shek – she was a student activist, fighting his regime – and through Mao’s rule. She’s 88 now and living in China.

Do you visit her?

Not often, because since the publication of my biography of Mao [in 2005] I’ve lost the freedom to travel in China. I’m allowed to go back 15 days a year to see my mother.

How does that feel?

I feel very bad. She’s just come out of hospital. I wish I could just jump on a plane and go and see her. Fortunately, we can Skype. My mother is extraordinary. I still draw strength from her capacity to make me feel that everything is OK, that I should just be myself. She can take anything: glory, danger, hardship.

Asking questions has been at the heart of your research process…

My mother inspired me to ask questions. She came to stay with me in 1988 and said, “I want a serious talk”, and started to tell me stories including how she and my father had to walk from Manchuria to Sichuan, a journey of more than 2,000 miles. My mother suffered a miscarriage on the way. As she was talking, I began to think I must write all this down.

How did it shape you growing up in a country with cultural censorship?

I had always wanted to be a writer as a child but couldn’t spell out this dream to myself because during the Cultural Revolution all writers were condemned. To be a writer was the most dangerous profession. I wrote my first poem aged 16 and destroyed it. When I was working spreading manure in the paddy fields aged 16 and 17, I was always writing in my head. In my home town there was a black market selling books that had been banned. My 13-year-old brother was very entrepreneurial. He made money dealing Mao badges and used it to buy books, which he hid in a hole he dug in the garden.

So you’ve always felt the power of words…

Huge, huge power. My father loved writing and encouraged us to write diaries. But I had to destroy my diary during the revolution.

What are your early memories of living under Mao?

I was in nursery school aged about four and my mother came to see me but had to return to detention before midnight [during the Cultural Revolution, Chang’s parents were denounced, imprisoned and tortured]. I remember she held my hand through the barrier and then pulled her hand away and was gone because her time was up.

Mao ordered flowers to be destroyed…

When I was in school we all had to go out and remove grass from the school lawn as he had just issued the order that cultivating flowers and grass was a bourgeois habit. In my house there was always a vase with flowers – one day it disappeared, and the parks became wastelands. When I first came to Britain and saw flowers I was beside myself with joy.

The People’s Republic of China celebrated its 70th anniversary on 1 October but it’s been a turbulent year, with the protests in Hong Kong…

While researching my book I discovered that there was a period between 1913 and 1928 when China was practising democracy – and people took to it with remarkable ease. So it’s not something completely alien to the Chinese. I’m holding my breath and waiting to see what happens.

You’ve witnessed some of the most brutal periods of history. Are you an optimist?

It’s impossible to return to those brutal periods now. I feel on the whole the world is moving forward, although there are many attempts to turn the clock back, but I think we’re in a more civilised and humane world. I’m feeling hopeful.

• Jung Chang is at Southbank Centre’s Queen Elizabeth Hall, London, on 19 October

• Big Sister, Little Sister, Red Sister: Three Women at the Heart of Twentieth-Century China is published by Jonathan Cape (£25). To order a copy go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £15, online orders only. Phone orders min p&p of £1.99