‘Not necessarily.’ Huang Yiyi stepped right into the firing line as she said firmly, ‘What is a cipher other than an unusually abstruse mathematical problem? There’s nothing to be afraid of there.’

Her words transfixed both Comrade Chen and me. After a long pause, Chen replied respectfully, ‘OK. Let’s see what you can do.’

‘No, you have a part to play too.’ She turned her head to speak to me. ‘Deputy Director An, I hope that Bureau Chief Chen will join our little cryptographic working party!’ Then she walked out and did not stop no matter how much I yelled after her.

Comrade Chen was one of the founders of the cryptography division, and he had now been a Bureau Chief for more than ten years, in addition to which he was one of the deputy directors of Unit 701, though that was in fact largely honorific given that he was also the cryptography Bureau Chief. How could she expect Comrade Chen to go and work as her assistant! But when I went to discuss the matter with her she refused to back down, and insisted that she wanted Chen to take part. ‘I don’t need an assistant; I need someone to quarrel with!’ She was resolute, and spoke persuasively about the reasons why she wanted Comrade Chen to join us. ‘Neither you nor I know the first thing about how cryptography is done here, in addition to which they have never cracked a real high-level cipher, so fundamentally they don’t have a hope in hell of breaking RECOVERY. That means that if we see the way that they go about trying to crack it, we will know what to avoid.’ This put me in mind of something that Anderov used to say: that cracking codes isn’t like a duel – you need scapegoats! You let other people fall into the traps, so that you can walk round them.

I looked at her in alarm, horrified by this nasty idea. But I had no right to refuse her, given that her request was actually perfectly logical. At that moment cracking RECOVERY was our most urgent and high-priority assignment, and this was not the time to worry about what methods we used, whether against the enemy or against ourselves. That’s what cracking a cipher is like; it’s an unpleasant profession, full of darkness and danger.