‘Of course I’ve heard of her.’ She was well known in the Soviet Union: a very strange woman – a brilliant mathematician but also exceptionally arrogant. I had heard that one time Stalin invited her to lunch but she refused because she wanted to go and watch a football match. Naturally Stalin made her pay for that, and in the end she was forced to seek asylum in the US.

‘Do you know what she has been doing since her arrival in the States?’ Liu asked me.

‘I do. She has been writing ciphers for the Americans.’

‘I see that you do actually know something about her. Anyway, at university she was one of your supervisor Anderov’s fellow students, and they were pretty close.’

‘I know. Anderov often mentioned her. I suppose you know that after she got to the States she wrote a cipher for the US military called DIFFICULT CENTURY which is said to be one of the most complex ever devised. In the end, though, the Americans didn’t dare use it. After all, she is Russian.’

Liu said that he knew all about that, and then he asked, ‘Do you know what happened to her cipher?’

‘No.’

‘Well, I do.’ He handed me a heap of documents and told me to read them. ‘The cipher that we need to crack, RECOVERY, is none other than Liljeva Sivincy’s DIFFICULT CENTURY.’

I simply couldn’t believe it.

It was true, though. According to Bureau Chief Liu, the Americans did not dare use this cipher themselves but they thought it would be a shame just to waste it, so they gave it to Taiwan. The KMT were absolutely thrilled about it. The documents slipped from my grasp … I was in the grip of a strong psychological reaction; everything went dark, my legs buckled under me, it felt as though the blood was draining from my body … That night I wrote a report for Director Tie pointing out that this was no ordinary code, but an algorithmic cipher of the utmost complexity. In my opinion, having read the résumés of our current staff, there was no way that we could crack it. If we wanted to break it, we would have to bring someone in from outside, and it would have to be a mathematician of the very first order. I also put it on record again that I was simply not qualified for the job, and recommended that the Party find someone else to lead the team to crack RECOVERY.

The following afternoon, Secretary Li popped up. Trotting along behind him was Director Tie. He came into my room and said with a smile, ‘You know more than the rest of us do about Liljeva Sivincy.’

‘She was at university with my supervisor, Anderov,’ I said.

‘So now you should understand why we insisted on appointing you.’

‘But there is no way I’m qualified to do this – I’m not a mathematician …’