There were just as many stories told about Huang Yiyi at Unit 701 as there were about the blind man, Abing, though these stories were much coloured by the opinions and personalities of the speakers. It was fascinating, though, and really made me want to write about Huang Yiyi, the only woman cryptographer ever to have become a Bureau Chief in the history of Unit 701. But I didn’t dare, because I hadn’t been able to meet the person most closely involved, a man as important to her story as Director Qian was in what happened to Abing. That man was the fourth head of Unit 701, Director An.

Director An was a very, very senior figure indeed: he was one of the nine original members of Unit 701, known as the ‘Nine Gentlemen’. Now well past eighty, he was the only surviving Gentleman. His health was still good though: when we shook hands his grip was strong, and he spoke perfectly clearly, though I sometimes had trouble understanding his thick Western Zhejiang accent. He had been living since his retirement in an out-of-the-way little town in the north, a place that was neither his home town nor anything to do with his work, but which had in fact been picked for him by his one-year-old grandson. The venerable Mr An was quite an unusual man: when he retired he didn’t want to go to any of the big cities like Beijing or Shanghai; he asked the Party to arrange for him to live in a city he had never been to before. He didn’t care which one, just somewhere new! That really did put the Party to a lot of trouble. China is so big, with so many places that he had never been to: so how to choose? In the end he took over the decision-making process himself and got his baby grandson to throw a coin on to a map of China: wherever the coin landed, that was where he would live. It was a fatalistic way of resolving the problem. Ever since then, he had had no contact with Unit 701, and so it was not easy to find him after all that time.