The most momentous trade route in Asia is not marked on any state cartography. It does not feature in economic surveys, permeate in infrastructure summits or govern headlines like nautical bottlenecks and energy corridors. Despite this, it traverses some of the continent's geopolitically charged, vulnerable terrain from the hinterlands of Afghanistan and the deserts of Iran to the untamed highlands of Myanmar and the turbulent borderlands of Northeast India. Its freight is ne

In 1826, the British government established a border between India and Burma that cut through villages and even individual homes. This...