'Sun Gate'), is a mountain pass that was fortified by Emperor Wu of the Western Han dynasty around 120 BC and used as an outpost in the colonial dominions adjacent to ancient China.

In a famous poem, "Seeing Yuan'er off on a Mission to Anxi", the Tang dynasty poet Wang Wei wrote: The morning rain of Weicheng dampens the light dust, The guest house is green with the colour of fresh willows.

Let's finish another cup of wine, my dear sir, Out west past the Yangguan, old friends there'll be none.

Wang Wei's poem inspired one of China's best-known musical pieces, the "Three Variations of Yangguan" (Yangguan Sandie, traditional Chinese: 陽關三疊; simplified Chinese: 阳关三叠) which existed as early as the Tang dynasty.

[3] A current popular version is based on a late Qing dynasty tune; originally it was played on guqin and first published in Introduction to Learning Qin (琴學入門, Qinxue Rumen) in 1864, but it may be traced back to a version from the Ming dynasty.