For the majority of the duration of Chinese history, China's western borders were filled with small principalities. The majority of them swears allegiance to the Chinese Emperor, but some powerful ones cause troubles every few decades or so. The Chinese never emphasized these relations and the western lands in general, and the emperors generally give all powers on such matters to the governor and military general of the bordering province. And technically anyone in China above the bureaucratic title of "Justice of County" is superior to a western prince, showing the ignorance the ancient Chinese had.
The Great Wall
The system of secret escape routes that led enslaved people to free lands was called the Underground Railroad. It was a network of safe houses, abolitionists, and hidden routes that helped enslaved individuals escape to free states or Canada. The network operated in the United States before the Civil War.
The Silk Road or network of trade routes across the Asian continent connected East, South, and Western Asia with the Mediterranean world, as well as North and Northeast Africa and Europe. It encouraged development by opening the lands through trade.
Population density varies strikingly, with the greatest contrast occurring between the eastern half of China and the lands of the west and the northwest.
It was usually merchants who traveled to foreign lands when the sea routes opened. Having access to sea routes and ships allowed them to trade their merchandise in foreign countries in return for items they had never seem before.
The Muslims.
They ruled the great trading routes
forts
yes
Yes
Trading Posts
China in the north, South Korea in the south.
A system of people in different lands who trade goods back and forth is known as a trade network.