During the Han Dynasty, which region was referred to as the Western Regions? What was the name of the traditional trade route through this area?

During the Han Dynasty, the Western Regions in a narrow sense meant the area west of the Yumen Pass and the Yangguan Pass, east of the Onion Ridge, which is now the Pamir Plateau, and east and south of Lake Balkhash, as well as the vast area of Xinjiang. And the broad sense of the Western Region is to refer to any through the narrow sense of the Western Region can reach the region, including the central and western regions of Asia, etc..

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The traditional trade route through this area is called the (Silk Road)