I was standing on top of a cliff looking at a loudspeaker the size of a small block of flats facing out to sea. There was music playing, the woman’s voice so loud it hurt my ears. But this was down to the vastness of the speaker, not the song, which was plaintive and mellifluous and heartbreaking, even though I couldn’t understand a word.

The music stopped. The woman talked, in Mandarin, the recording crackling. “Dear friends in mainland China,” she said, my guide, Chifa Chen, translating. “I am happy to be here in Kinmen. I hope you can share the same freedom. Please, just come here and realise your dreams.”

I turned to face the sea, following the woman’s voice. Across the strait, just six miles away, through the diaphanous smog, I could see the ghostly skyscrapers of Xiamen city in mainland China. The voice, Chen told me, was the late Teresa Teng’s, Taiwanese folk singer and soldiers’ sweetheart, whose patriotic ballads of the 1970s, blasted nightly across the strait, were a potent propaganda tool in the cold war between Taiwan and China. Despite being banned at one point, Teng enjoyed huge popularity in China, where lovestruck fans christened her “Little Deng” (on the mainland, her name was spelt in the same way as China’s then leader). “It is said that Deng Xiaoping ruled China by day,” said Chen. “But Deng the singer ruled China by night.”