Ibrahim meanwhile continued to work away at his great reconciliation of the two religions, colliding now in Gansu right before their eyes. The Gansu Corridor was the great pass between the east and west halves of the world, and the long caravans of camels that had headed cast to Shaanxi or west to the Pamirs since time immemorial were now joined by immense trains of oxen hauled wagons, coming mostly from the west, but also from the east. Muslim and Chinese alike settled in the region, and Ibrahim talked to the leaders of the various factions, and collected texts and read them, and sent letters to scholars all over the world, and wrote his books for many hours every day. Kang helped him in this work, as he helped her in hers, but as the months passed, and they saw the increasing conflict in the region, her help more and more took the form of criticism, of pressure on his ideas – as he sometimes pointed out, when he felt a little tired or defensive.

Kang was remorseless, in her usual way. 'Look,' she would say, 'you can't just talk your way out of these problems. Differences are differences! Look here, your Wang Daiyu, a most inventive thinker, takes great trouble to equate the Five Pillars of the Islamic Faith with the Five Virtues of Confucianism.'

'That's right,' Ibrahim said. 'They combine to make the Five Constants, as he calls them, true everywhere and for everyone, unchanging. Creed in Islam is Confucius's benevolence, or ren. Charity is yi, or righteousness. Prayer is li, propriety, fasting is shi, knowledge. And pilgrimage is xin, faith in humankind.'

Kang threw her hands up. 'Listen to what you are saying! These concepts have almost nothing to do with each other! Charity is not righteousness, not at all! Fasting is not knowledge! And so it is no surprise to find that your teacher from the interior, Liu Zhi, identifies the same Five Pillars of Islam not with the Five Virtues, but with the Five Relationships, the Wugang not the Wuchang! And he too has to twist the words, the concepts, beyond all recognition to make the correspondences between the two groups fit. Two different sets of bad results! If you pursue the same course they did, then anything can be matched to anything.'

Ibrahim pursed his lips, looking displeased, but he did not contradict her. Instead he said, 'Liu Zhi made a distinction between the two ways, as well as finding their similarities. For him, the Way of heaven, tiando, is best expressed by Islam, the Way of Humanity, rendao, by Confucianism. Thus the Quran is the sacred book, but the Analects express the principles fundamental to all humans.'

Kang shook her head again. 'Maybe so, but the mandarins of the interior will never believe that the sacred Book of Heaven came from Tiangfang. How could they, when only China matters to them? The Middle Kingdom, halfway between heaven and earth; the Dragon Throne, home of the Jade Emperor – the rest of the world is simply the place of barbarians, and could not possibly be the origin of something as important as the sacred book of Heaven. Meanwhile, turning to your shaikhs and caliphs in the west, how can they ever accept the Chinese, who do not believe at all in their one god? This is the most important aspect of their faith!' And she muttered, 'As if there could ever only be one god.'

Again Ibrahim looked troubled. But he insisted: 'The fundamental way is the same. And with the empire extending westwards, and more Muslims coming east, there simply must be some kind of synthesis. We will not be able to get along without it.'

Kang shrugged. 'Maybe so. But you cannot mix oil and vinegar.'

'Ideas are not chemicals. Or, they are like the Daoists' mercury and sulphur, combining to make every kind of thing.'

'Please don't tell me you plan to become an alchemist.'

'No. Only in the realm of ideas, where the great transmutation remains to be made. After all, look at what the alchemists have accomplished in the world of matter. All the new machines, the new things…'

'Rock is much more malleable than ideas.'

'I hope not. You must admit, there have been other great collisions of civilizations before, making a synthetic culture. In India, for instance, Islam invaders conquered a very ancient Hindu civilization, and the two have often been at war since, but the prophet Nanak brought the values of the two together, and that is the Sikhs, who believe in Allah and karma, in reincarnation and in divine judgment. He found the harmony beneath the discord, and now the Sikhs are among the most powerful groups in India. Indeed, India's best hope, given all its wars and troubles. We need something like that here.'

Kang nodded. 'But maybe we have it already. Maybe it has been here all along, before Mohammed or Confucius, in the form of Buddhism.'

Ibrahim frowned, and Kang laughed her short unhumorous laugh. She was teasing him while at the same time she was serious, a combination very common in her dealings with her new husband.

'You must admit, the material is at hand. There are more Buddhists out here in these wastelands than anywhere else.'

He muttered something about Lanka and Burma.

'Yes yes,' she said. 'Also Tibet, Mongolia, the Annamese, the Thais and Malays. Always they are there, you notice, in the border zone between China and Islam. Already there. And the teachings are very fundamental. The most fundamental of all.'

Ibrahim sighed. 'You will have to teach me.'

She nodded, pleased.

In that year, the forty third year of the reign of the Qianlong Emperor, an influx of Muslim families greater than ever before came in from the west on the old Silk Road, speaking all manner of languages and including women and children, and even animals. Whole villages and towns had emptied and their occupants headed east, apparently, driven by intensifying wars between the Iranians, Afghans and Kazakhs, and the civil wars of Fulan. Most of the new arrivals were Shiites, Ibrahim said, but there were many other kinds of Muslims as well, Naqshabandis, Wahhabis, different kinds of sufis… As Ibrahim tried to explain it to Kang, she pursed her lips in disapproval. 'Islam is as broken as a vase dropped on the floor.'

Later, seeing the violent reaction to the newcomers from the Muslims already ensconced in Gansu, she said, 'It's like throwing oil on a fire. They will end up all killing each other.'

She did not sound particularly distressed. Shih was again asking to study in a jahriya qong, claiming that his desire to convert to Islam had returned, which she was sure represented only laziness at his studies, and an urge to rebellion that was troubling in one so young. Meanwhile she had had ample opportunity to observe Muslim women in Lanzhou, and while before she had often complained that Chinese women were oppressed by men, she now declared that Muslim women had it far worse. 'Look at that,' she said to Ibrahim one day on their riverside verandah. 'They are hidden like goddesses behind their veils, but treated like cows. You can marry as many as you like of them, and so none of them have any family protection. And there's not a single one of them who can read. It's disgraceful.'

'Chinese men take concubines,' Ibrahim pointed out.

'Nowhere is it a good thing to be a woman,' Kang replied irritably. 'But concubines are not wives, they don't have the same family rights.'

'So things are only better in China if you are married.'

'This is true everywhere. But not to be able to read, even the daughters of the rich and educated men! To be cut off from literature, to be unable to write letters to your birth family…'

This was something Kang never did, but Ibrahim did not mention that. He only shook his head.

'It was far worse for women before Mohammed brought Islam to the world.'

'That says very little. How bad it must have been before, and that was over a thousand years ago, correct? What barbarians they must have been. By then Chinese women had enjoyed two thousand years of secure privileges.'