In the West part of China, The Xinjiang, formerly East Turkestan, sorrounds the Tarim basin and the Takla Makan desert. Here the oasis of Khotan, Yarkand and Kashgar, part of the Silk road, originally populated by Turkic tribes, were active trade centers and famous for rugs weaving. In the West, these carpets were sold in the bazaar of Samarknd and in the East in the one of Gansu. For this reason they were often called Samarkand and Gansu carpets ( Gansu was a weaving center as well ) In my humble opinion it is very difficult to clearly differenciate the three groups of carpets and to attribure specific structural carachteristics and designs.