From Shahidulla, merchants bound for the Tarim Basin had three choices: the Kilik, the Kilian, and the Sanju. Each had its partisans and its problems. The Kilik was reportedly the easiest and shortest, with ample fodder and fuel at every stage, but political restrictions kept most traders off it, and seasonal flooding of the Toghra river could block access for weeks. The Kilian had once been the most popular crossing, but by the 19th century it had fallen out of regular use; its summit was permanently ice-covered and impassable for laden ponies, requiring yaks instead. That left the Sanju as the default, the pass that worked well enough often enough. After cresting it, caravans descended to the village of Sanju, from which a good road led 122 miles to Yarkand, linking up with the other routes at Bora and Karghalik.

The trade flowing across the Sanju Pass connected two distinct worlds. To the south lay Ladakh and, beyond it, the markets of northern India. To the north lay the Tarim Basin: Yarkand, Khotan, Kashgar, the ancient oasis cities strung along the southern branch of the Silk Road. Goods moved in both directions: tea, textiles, and spices heading north; jade, silk, and dried fruit heading south. The Chinese had mined jade in the upper Karakash River region since at least the Later Han Dynasty, and the Kunlun Mountains were one of the most prized sources of nephrite in the ancient world. Balti merchants based in Yarkand were among the most active traders on these routes, their pack animals carrying loads between civilizations that differed in language, religion, and every custom except the universal desire to buy and sell.

When the Dungan Revolt shook Xinjiang in 1862, the political status of the entire region became uncertain. The Maharajah of Kashmir, sensing an opportunity, built a fort at Shahidulla and stationed troops there to protect the caravan routes. It was a bold claim, extending Kashmiri control all the way to the Kunlun Mountains. But the claim did not hold. By the time Francis Younghusband explored the region in the late 1880s, the fort was abandoned and Shahidulla was little more than a staging post for nomadic Kirghiz. Thomas Douglas Forsyth, who led a British mission to Kashgar in 1873-74, found Kashmiri and Yarkandi outposts sitting just two stages apart on either side of the Karakash River, an early and uneasy example of coexistence. Forsyth recommended drawing Kashmir's boundary north of the Karakash valley, but it is doubtful the line was ever formally established.

The Qing dynasty crushed the Dungan Revolt in 1878 and reasserted control over the entire region. When the Maharajah of Kashmir indicated a wish to reoccupy Shahidulla in 1885, the British themselves prevented him, and the territory remained under effective Chinese authority. It has been part of Xinjiang ever since. The Sanju and Kilian passes lie well to the north of any territory now claimed by either India or Pakistan. Today, China National Highway 219 runs from Kargilik in the Tarim Basin south through Shahidulla and across the disputed Aksai Chin region into northwestern Tibet. The old caravan routes have been overlaid by strategic roads, and the geopolitical tensions that once played out between Kashmiri forts and Yarkandi outposts now take the form of standoffs between the world's two most populous nations.

The Sanju Pass spent most of the 20th century in obscurity, bypassed by the Karakoram Highway further west and closed off by the political boundaries of modern China. But in recent years it has found a second life. Chinese trekkers have taken to the old route, drawn by its remoteness and its history. In the early 2020s, an unpaved scenic road was opened along the trail for adventurous drivers, threading through the Kunlun foothills on what may be one of the highest auto-touring routes in China. The caravans are gone, but the pass endures. At 5,364 meters, the Kunlun wind still blows across the summit as it did when Balti merchants drove their pack trains toward Yarkand, carrying jade south and ambition north across the roof of the world.