The Sogdian Ancient Letters

evidence

Five substantially surviving letters of Sogdian merchants, undelivered, showing how the eastern routes actually operated: resident family colonies in a chain of cities from Sogdiana to the Hexi Corridor, goods moved between them in relays, business conducted by correspondence and credit rather than by single long journeys. Letter 2 reports the sack of Luoyang, which anchors the conventional dating to around 313 CE. The letters are written on paper, establishing that the material had reached the far western Chinese frontier by that date.

A evidence is not a place. Drawing it on a map would assert something about the world that no stored fact supports.