Читать книгу China: A History - John Keay - Страница 33

After coming of age, in 135 BC Han Wudi had signed another ‘peace-through-kinship’ treaty with the then shanyu. The matter had sparked a heated debate in Chang’an, and this had flared again in 134 BC when, with Xiongnu suspicions disarmed by the latest tribute bonanza, prospects for a surprise counter-strike, not to say a perfidious one, seemed particularly favourable. Old arguments were rehearsed, revenge of Gaozu’s defeat at Pingcheng was reinvoked, and Wudi now sided with the hawks; an elaborate plan was approved for luring the shanyu into an ambush in the town of Mayi (in northern Shanxi).

This time there was no disaster, just dismal failure. The Xiongnu got wind of the trick, wheeled about, vanished into the steppe, and repudiated the treaty. Five years of ‘phoney war’ ensued. Xiongnu raids continued but so did the frontier markets, at which cross-border trade flourished as never before. It was all part of the plan. In autumn 129 BC, when the markets were at their busiest, Han armies swooped on four of them. Despite the element of surprise, only one attack was moderately successful. Xiongnu losses were put in the hundreds, Han’s in the thousands, and Pingcheng remained unavenged. But two years later Wei Qing, brother of the emperor’s favourite consort and one of half a dozen charismatic generals to emerge at this time, redeemed the Qin First Emperor’s conquests by retaking the Ordos. It was ‘the first major setback for the Xiongnu since the days of Maodun’.⁶ Qin’s ‘Great Wall’ defences were reoccupied and settlements re-established on either side of the Yellow River’s northern bend.

This brought retaliation from the Xiongnu both east and west of the new salient and was followed by devastating countermoves from the Han. Throughout the 120s BC scarcely a year passed without ever larger Han expeditions probing ever deeper into Xiongnu territory. By 119 BC they were pushing north right across the Gobi desert into Outer Mongolia and north-west through Gansu to Ningxia. Han armies were now matching the Xiongnu for mobility and could support themselves in the field for several months. New commanderies, crammed with labour camps and soldier-settlers, ensured the security of the ‘Great Wall’ frontier, while Xiongnu losses, especially of livestock and pasturage, induced dissent within the nomadic confederation. The consequent defections may partly account for the improved performance of the Han forces as these new allies were deployed against their erstwhile comrades.

Success was real, but the price high. Sima Qian follows official practice by ‘scoring’ each engagement as if it were a rubber of bridge, or an exam paper. From his totting up of the hundreds of thousands of troops involved, the tens of thousands slain, the numerous generals and chieftains captured, and the vast herds of sheep, cattle and horses corralled, it appears that, for the Han, acceptable losses ran as high as 30 per cent and sometimes reached 90 per cent. If anything, the Xiongnu fared better in this respect – and they needed to; for while Han resources of manpower and provisions were practically inexhaustible and constrained only by the logistics of deployment, nomadic numbers were finite, their livelihood in terms of flocks and herds was vulnerable, and their only asset lay in the limitless terrain.

Having reclaimed the northern frontier and scattered the enemy, the Han might have scaled down their operations after 119 BC. That they would do no such thing looks to have been due to the intelligence-gathering of explorer Zhang. For although the exact chronology is uncertain, it seems to have been at about this time that his information on central Asian affairs was reviewed, he himself re-examined, and a new direction given to Han’s expansionist momentum. Instead of pushing ever farther north into the unrewarding wastes of Mongolia, Chang’an’s troops would veer west and set their sights on the flourishing states of central Asia, as reported by Zhang.

Initially Zhang’s discoveries had served as a distraction. In the course of his western odyssey, the explorer had crossed the deserts of Xinjiang, scaled the bleak Pamirs and descended to both the Syr Darya (Jaxartes River) and Amu Darya (Oxus River). The region along the former was called ‘Dayuan’, otherwise Ferghana and now eastern Uzbekistan, that along the latter ‘Taxia’, otherwise Bactria or northern Afghanistan. Since the Yuezhi had just overrun Bactria, they showed no interest in returning east of the Pamirs to oblige Chang’an in its feud with the Xiongnu. Their future lay south of the Himalayas, where they would be known as the Kusana (Kushan), would found one of northern India’s greatest empires, and in the first century AD would repay Zhang’s visit by sending to China the first Buddhist missionaries. But as yet ignorant of ‘the Enlightened One’, the Yuezhi in the early 120s BC opened explorer Zhang’s eyes only to the importance of the strange world into which he had blundered.

Had it not been for his decade-long detention by the Xiongnu, Zhang would have found Greek-speaking kings with names like Euthydemus and Menander still ruling in Bactria. Relics of Alexander the Great’s expedition, these Bactrian kings had been ejected by the Yuezhi in 130 BC, just months before Zhang’s arrival. Their magnificent gold and silver coinage was still in circulation and surprised Zhang by its novel use of portraiture. Each coin, he reports, ‘bore the face of the king [and] when the king died, the currency was immediately changed and new coins issued with the face of his successor’. Such a practice had never been known in China; since it could be construed as ennobling commerce and demeaning the sovereign by association with it, nor would it be.

West of Bactria stretched the great kingdom of ‘Anxi’, otherwise Parthia or Persia (Iran), where the Seleucids, also legatees of Alexander’s empire, had earlier been overthrown by the Parthian Arsacids; this Anxi extended to what Zhang calls ‘the western sea’, which is thought to be the Gulf rather than the Mediterranean. East of Bactria, the kingdom of ‘Shendu’ was of more interest. While exploring the Bactrian bazaars, Zhang had noticed ‘cloth from Shu [Sichuan] and bamboo canes from Qiong [also in Sichuan]’, both of which were said to have been imported via ‘Shendu’. Although some of explorer Zhang’s place-names are hard to identify, there is no question that ‘Shendu’ was India; its inhabitants ‘rode elephants into battle’ and even the Romans knew the country as ‘Sindu’ (after the Sind, or Indus, River). Since it was said to be several thousand kilometres east of Bactria, Zhang reasoned that it must ‘not be very far away from Shu’. Silk cloth and bamboo canes must therefore be reaching India direct from China’s extreme south-west.

Of all Zhang’s revelations, this was the one that had at first excited the most interest in Chang’an. As his ten years of Xiongnu captivity had demonstrated, access to central Asia was as yet fraught. Across the deserts of Xinjiang the Xiongnu controlled the route north of the ‘Great Swamp’ (nowadays the salt desert of Lop Nor), while Xiongnu allies, the proto-Tibetan Qiang, controlled that south of it. Only the cane-and-silk route from Sichuan to India and Bactria looked to offer a way of circumventing both. When Zhang had proposed that he lead a secret expedition to explore it, ‘the emperor was delighted’.