As Robert Clark notes in The Global Imperative, "there is no doubt that trade networks like the Silk Road made possible the flourishing and spread of ancient civilizations to something approximating a global culture of the times."1 Goods, people and ideas all travelled along these long-distance routes spanning or circumventing the vast landmass of Eurasia. From earliest times, there have been three main routes, which connected China with the outside world.2 These were the overland routes that stretched across Eurasia from China to the Mediterranean, known collectively as the "Silk Road"; the Spice Trade shipping routes passing from the South China Sea into the Indian Ocean and beyond, known today as the "Maritime Silk Road"; and the "Southwestern Silk Road," a network of overland passages stretching from Central China through the mountainous areas of Sichuan, Guizhou and Yunnan provinces into the eastern states of South Asia. Although the first two routes are better known to students of World History, the Southwestern Silk Road has a long ancestry and also played an important role in knitting the world together. Marco Polo himself wrote of his travels along the spur of this route into Tibet following the Mongol conquest of the Dali kingdom of Yunnan in the early 13th century.3 Moreover, the Southwestern Silk Road has remained relevant even through the present day. One of the main routes from Kunming into north central Myanmar was revived with the creation of the 717-mile-long "Burma Road" logistical supply line of WWII. A section of this same route carries convoys of lumber-laden trucks across the Sino-Burmese border today as part of the modern Dian-Myanmar Highway (dianmian gonglu 滇緬公路).
Ancient East-West Connections
     The Southwestern Silk Route was an important point of contact between the two great civilizations of China and India, as well as a major conduit for the passage of East-West trade. Bin Yang in his recent book on the Southwestern Silk Road, Between Winds and Clouds: The Making of Yunnan, concluded that the southwestern route supported regional trade between China and India since at least the third century BCE, but that current archeological evidence does not provide enough detail to confirm either the volume or specific nature of trade in this earlier period.4 There is the oft-cited account from the Sima Qian's Records of the Historian (Shiji 史記), in which Zhang Qian 張騫 (d. 133 BCE), chief envoy of the Han emperor Wudi 武帝 (r. 141-87 BCE) visited the region of Afghanistan -- then known as Bactria (Daxia 大夏) -- in 122 BCE.

In Bactria Zhang saw merchants from northern India (Shendu 身毒) peddling two trade articles from the Shu 蜀 region (modern-day Sichuan),: "Qiong bamboo poles" (qiongzhu zhang 邛竹杖) and "Shu brocade" (Shujin 蜀錦).5 Zhang Qian concluded that there must be a direct trade route from Sichuan to India to the south, because northern routes were then in the hands of rival Qiang 羌 and Xiongnu 匈奴 chieftains.6 Zhang's account is the first documented claim for such a route in the Chinese historical record. The regional market for these trade items continued to grow throughout the early Imperial period. Qiong bamboo (Qiongzhuea tumidissinoda) was first grown in Qiongdu 邛都, which is today part of Xichang 西昌, a town in Sichuan that is now better known for satellite launches than it is for bamboo. Shu brocade was a variety of woven silk cloth, or, as other scholars argue, a type of linen that had been produced in Sichuan since the Warring States period (475-221 BCE), at which time it was already widely imitated.7 Following Zhang Qian's discovery, domestic trade in Shu brocade continued to grow. The Han emperor Chengdi 成帝(r.32-7 BCE) ordered that Yizhou 益洲 (near modern Chengdu) officials collect and transport three years' worth of taxes in local Shu brocade to produce seven fully finished brocade robes.

8 From the fall of the Han through the establishment of the Sui (581-618 CE), most of China suffered from periodic turmoil that affected local economic production. However, the Xichuan region was largely unaffected by the interregional fighting, and brocade production continued largely unabated. During the Tang, the central court continued to accept cloth brocade as tribute (gongjin 貢錦) from Sichuan, and a market for Shu brocade could still be found in the "Western Regions (Xiyu 西域)," including modern-day Xinjiang and other parts of Central Asia.
     Along with Qiong bamboo and Sichuan brocade, other local products such as Shu ironware and cinnabar could be found along the Southwestern Silk Road routes as far west as India and Afghanistan. West Asian, Indian and Burmese glassware, gem stones and pearls were the primary products that made their way into China as imports. The specific trade articles of the Southwestern Silk Road contributed to the definition of the network itself, emphasizing certain trade routes over others. As Bin Yang notes, Yunnan shared the mineral wealth of northern Myanmar (Burma) as a location rich in gold, silver, tin, lead, and copper deposits, among other minerals.9 However, interregional exchanges were not limited to luxury commodities. Guanghan, located to the south of Chengdu, is the site of the ancient Sanxingdui 三星堆 bronze culture that flourished as it borrowed from southern China to the east and the various non-Han kingdoms to the south, while remaining distinct from the Anyang bronze culture of the North China Plain.10
Traveling the Road
     The starting point of the Southwestern Silk Road on the Chinese side was modern Sichuan's provincial capital of Chengdu. The primary route passed through Yunnan, Myanmar (Burma), and into South Asia. This route, known as either the "India Route (shendu guo dao 身毒國道)" or the "Old Sichuan-Yunnan-Myanmar-India Route (chuan dian mian yin gudao 川滇緬印古道), split into two main branches as it passed through Sichuan into Yunnan. One branch, known as the "Old Yak Route (gu maoniu dao 古旄牛道)" extended from Chengdu southwest across the Sichuan Basin plain to the foothills of Mingshan 名山 mountains. 11 From here the route continued southwest along the Qingyi 青衣 River to Ya'an 雅安, once an important center for tea trade with connections through the Tibetan Plateau, linking up with the "Tea and Horse Trade" routes to Tibet, an important offshoot of the Southwestern Silk Road. The "Tea and Horse Trade" was important, because it illustrates a strong reciprocal relationship between China and its neighbors; Tibetans desired tea for use in meditation and for added nutrition, while war horses were vital to the Chinese dealing with aggressive nomadic cavalries to the north.12 Chinese courts until the Ming dynasty utilized tea as a precious commodity to trade with the Tibetans and other upland peoples of Sichuan and Yunnan for the valuable horses that were bred in the western region.13 This route to Lhasa, about 1500 miles in length, carried merchants and pilgrims between these two regions for 4,000-5,000 years.14 As Tansen Sen writes, the shortest route between India and China by the Song (960-1279) period was through Tibet.15 Along these routes travelers carried on trade in Buddhist religious articles through the 11th century.16
     For travelers engaged in trade with Southeast Asian and South Asian centers, the route proceeded southward away from these Tibet linkages. From Ya'an these merchants and pilgrims traveled upstream along the Jinsha 金沙 River, winding in a southerly direction through a system of river valleys to Qiongdu 邛都, the ancient site of Shu brocade, and finally southwest to Dali 大理 on Lake Erhai, the seat of political power for the Dali Kingdom (937-1253 CE). From Dali one took one of three routes to cross through Myanmar (Burma) on one's way to present-day India. These routes were collectively known as the Bonan Route (Bonan dao 博南道) or the Yongchang Route (Yongchang dao 永昌道) in the Han period, and the Western Dian-Tianzhu Route (Xidian Tianzhu dao 西滇天竺道) in the Tang. The most traveled of these routes left Dali and proceeded south past the former garrison town of Baoshan 保山, through the rolling hills around Ruili 瑞麗, and across the modern Burmese border. Ruili still remains one of the most trafficked border-crossing towns on the Sino-Burmese border. From this point the route passed by Mogok, a town known for its gemstones, past the ancient temple-filled capitals of Bagan and Pyè, across the Arakan Yoma mountain range in western Myanmar through modern India's easternmost state of Assam to Bogra in Bangladesh, and finally to the river plains of the Ganges River.
Routes of the Spirit
     Religious teachings traveled the Silk Road routes as well. There is much controversy surrounding the earliest arrival of Buddhism on the Southwestern Silk Road. Several prominent Chinese scholars concluded in the 1980s that the arrival of Buddhism along the overland route through Southwest China predated its spread into the Central China Plain.17 This bit of historical revisionism now seems premature, as archaeological evidence indicates that the overland Southwestern Silk Road was only connected by the Eastern Han period, after Buddhist pilgrims had already crossed into the Han Empire to the north. Nonetheless, in areas of Sichuan and Yunnan one can see evidence of Buddhist statuary produced by pilgrims who arrived early in the Common Era.18 Almost all scholars agree that after the third century CE Buddhist pilgrims traveling along southwestern routes to and from South Asian centers of Buddhist learning increased considerably, thereby creating cultural overlaps of historical significance.19
     Buddhism entered the region of Southwest China by several different routes, and the three leading schools of Buddhist thought, Theravada, Mahayana, and Tibetan Buddhism all made their presence felt along different spurs of the Southwest Silk Road. The kingdoms of Nanzhao and Dali in turn absorbed elements of all three traditions. As mentioned above, the northeastern region of South Asia around Assam produced the original Tantric Buddhist teachings that spread to Tibet by way of the "Tea and Horse Trade" routes into northwestern Yunnan.20 Theravada teachings spread along maritime routes and through northern Mainland Southeast Asia into southern and central Yunnan. The southwest border region of Sipsongpannā has long practiced Theravada Buddhism, although this particular school may not predate the early Ming dynasty.21 Mahayana teachings came into eastern Yunnan from China and northern Vietnam. Buddhism had a profound effect on the political states that emerged along the Southwestern Silk Road before the period of Mongol conquest. Both the Nanzhao and the later Dali rulers of Yunnan enhanced their authority and political control with notions of Buddhist kingship.
     Islam began to spread more widely in the region in the 13th century with the Mongol Conquest of Southwest China, but after that point Muslim Hui merchants were able to settle in communities along the trade routes. The Mongol ruler Kublai Khan appointed Sayyid Ajali Omar Shams ud-Din, a native of Bukhara, governor-general of Yunnan, and filled other positions with high-ranking Muslim personnel. From the Ming dynasty caravan routes used by Hui merchants from Dali and Kunming southwest to Chiang Mai (in modern-day northern Thailand) became important trade routes, carrying 700 to 1,000 mules in trade by the nineteenth and twentieth centuries.22 From Chiang Mai and the Burmese trade market, this overland trade would also link up with ports on the Indian Ocean trade network, and circulate goods throughout the region. Chinese Muslims with roots in Yunnan were among the seamen taken on board by the eunuch admiral Zheng He, himself a Yunnan native, when he sought out able sailors for his famous seven voyages of the Star Fleet (1403-1433).
Silk Road in the Song (960-1279)
     By the early 10th century, trading activities conducted along China's long northern and western frontiers faced greater military obstacles than did Southwestern Silk Road or South Sea trade. The southern ports of Nanhai (modern-day Guangzhou) and Th?ng Long (modern-day Hanoi) offered products prized since the Han Dynasty, such as "incense, drugs, elephant tusk, rhinoceros horn, tortoiseshell, coral, parrots, kingfishers (and) peacocks."23 Numerous local chieftains throughout Southwestern China approached the Song shortly after the dynasty's founding because control of trade contacts with the larger courts of the region would be an important aspect of their political authority. Rulers of the Song preferred trade in the Southwestern Silk Road region, where vassal kingdoms displayed much less aggression than did their northern counterparts, and rare commodities could be obtained in the course of observing tributary protocol.
     The Dali kingdom lay at the center of regional trade in the Song dynasty. By the late Tang period, travel from the Burmese Pyè kingdom to Dali took approximately 71 days and travel from Dali to Chengdu took 75 days.24 Merchants travelled mostly on foot while goods were transported by mules oxen, or horses25 Traders likely did not travel the entire length of these routes, as evidence from later periods demonstrates, but instead focused their trading activity on particular circuits, selling their goods in prominent market towns to others who continued to forward these goods along other set routes.26 Tansen Sen writes that the earlier Nanzhao kingdom had kept the region at peace and its trade flourishing through the mid-9th century.27 In the Song the Dali maintained trade ties with its southern neighbors such as Bagan, which offered gold and cowries to continue trade links. Dali, in turn, supplied horses through Guangxi to the Song court, with which the Yunnanese kingdom also engaged in salt trade.28 This trend toward trade-centered ties would have a dramatic impact on imperial Chinese relations with these emerging frontier kingdoms. The Chinese leadership revived relations with Dali shortly after the fall of Kaifeng to the invading Jurchen and the establishment of the Southern Song capital at Hangzhou. The commodity that drew the Song court to Dali was horses, and at its height, this trade supplied around 1500 horses annually to Kaifeng from Yunnan.29  In sharp contrast to the once prevailing view that the Chinese court pursued relations with its neighbors through a "one size fits all" tributary system of ritual ties, it is important to note that trade shaped the Chinese empire's relations with the emerging kingdoms of Southeast Asia at the same time that debates about border security informed the court's policy toward its northern neighbors. When we take into account the Song's relations with kingdoms and smaller polities along the Southwestern Silk Road, we more easily see the Chinese empire in this period as flexible and adaptable in its relations with its neighbors, contrary to the inwardly-focused depiction of the Song in early Chinese historical literature.
     Silk Road connections and their role in facilitating trans-regional trade and cultural exchange have become increasingly prominent features of any general overview of world history. The significance of the Southwestern Silk Road should therefore not be overlooked. In the era of the "Great Game (1813-1907)," the Western discovery along northern Silk Road routes of the Mogao Grottoes of Dunhuang and other cultural artifacts focused scholars from Europe and North America on this region. In this same period the academic study of Southwest China and its historical trade ties throughout Mainland Southeast Asia was of interest to some Europeans, the French and British in particular. However, the center of archaeological activity remained in the north. Even today, the southwestern region has received far less attention in western scholarship, but this lack of interest will surely change in the future. In academic circles, the great amount of scholarship contributed by Chinese and Japanese scholars in different periods through the 20th century, and the recent work from Thai and Vietnamese scholars has brought a new prominence to Southwestern Silk Road studies in the larger picture of interregional systems of exchange in Eurasia. In political circles, China's Southwest has become a more important policy consideration as Beijing trade and security ties with its southern and southwestern neighbors, as evidenced by the recent proposal for a "Two Corridors and One Rim" regional cooperation between the northern provinces of Viet Nam and Laos and the southern Chinese provinces of Guangxi and Yunnan. Trade transportation, tourism and the development of special economic zones are all part of this proposal to revive transport ties along the former trade routes of the area.30
     Another important but under-examined aspect of trade throughout greater Asia is the connection between maritime and overland trade. Overland trade routes were often complimented by sea routes; the two types of networks worked in tandem. Between 750 and 1000 Arab traders from the Caliphate in Baghdad could travel by sea from the Persian Gulf through the Indian Ocean to the South China Sea or cross by land through former Sogdian territory into China's western region. The settlements of Arab traders in Sri Lanka in this period resulted in the connection of long-distance trade between the Persian Gulf region and China's southern seaport of Nanhai (Guangzhou).31 Further west along the South China coast was Hepu, often described the maritime gateway for merchants traveling to or from the easternmost sections of the overland Southwestern Silk Road.32 Along the way several seaports acted as starting points for northerly connections to the prevailing East-West overland routes that flourished when inland empires were at peace; in turn, these gave way to sea routes when the peace was lost. One such hybrid maritime-overland route involved Indian Ocean traders crossing the Bay of Bengal to land at the mouth of the Irrawaddy River and load or unload cargo that traveled the river valleys north to the southern spur of the Southwestern Silk Road mentioned above.33
     Such trade links fits well into the general trend of "Southernization" described by Lynda Shaffer in world historical terms, as Indian Ocean trade by Arab, South Asian and Southeast Asian seafarers created alternate routes for the 12th-century East-West circulation of goods between South China and the Mediterranean region.34 The important role maritime links played in sustaining overland routes through northern Southeast Asia into China's southern frontier until the end of the Song dynasty should not be ignored, just as we must keep in mind the complementary role played by Southwestern Silk Road in global connections.