The Institute of Mathematics at the Chinese Academy of Sciences was housed on the southern edge of the Haidian district of Beijing in a solitary, almost abandoned-looking building. That afternoon, having collected the documents from Captain Hu’s work unit, my route home took me past it, and so I wandered in as any member of the public could do. When I got through the gate, I noticed the statue of Zu Chongzhi shining in the sun. A bit further on there was a young man staring fixedly at the sun: as far as I could tell he was trying to work out the angle of declination. On my way out I spotted an old man, with the thick glasses of someone terribly short-sighted, bending down to pick up some potatoes that had fallen onto the ground from his basket. One of the potatoes had fallen into the gutter but he didn’t care, he put it back into his basket as if it were a treasure. Clearly the country was in a worse state than I had realized.

That evening, under the name Yang Xiaogang, I moved into the Institute’s guest house. The guest house at that time seemed very fancy to me, but then it was used to house foreign experts. There was a guard on the door, sitting behind a little desk, and he seemed to be keeping a careful eye on everyone who came and went. While I was arranging a room with the front desk, I noticed that there were two foreigners, a man and a woman, sitting in easy chairs in the entrance hall, chatting. I couldn’t understand what they were saying so I was sure that they weren’t Russian.

Approximately three hours earlier, Wang, the Secretary of the Party Committee at the Institute of Mathematics, had received an important phone call from the principal of the Chinese Academy of Sciences, announcing my arrival. The principal also instructed him, ‘Inform me the minute that he arrives.’ Before hanging up, he also told him, ‘This man is on a special mission: you must guarantee his personal security.’

The minute Wang put the phone down he rushed round to the guest house, waiting apprehensively for my arrival in the newly decorated main hall. Every so often he would go outside into the rain to peer into the distance, to see if I was on my way. Perhaps it was because he had really taken to heart his orders to treat me respectfully that he started looking out for me long before I could possibly have arrived. But when I did finally get there, he barely glanced at me and certainly didn’t say hello. There was certainly no sign of the warm welcome that I had been promised.