In ancient times, any tribe settled in a place for a long time, and its primitive and destructive labor would inevitably destroy the resources there and tend to dry up. The decline or salinization of land fertility, the narrowing of hunting and fishing areas and so on are inevitable, and the available food and other materials will only become less and less. In this case, there is only one choice, and the tribe must move to a new and better place.
When Kuafu encountered this problem, he decided to go west to Yugu at sunset.
This decision is incredible to modern people, because we know that the earth is spherical and revolves around the sun. The sun will not fall into the earth at all, let alone move westward, or be blocked by mountains or enter the desert. There are not many places suitable for human habitation. With the development of science and technology in 2 1 century, it is still difficult for people to live well in oases. As for the ancient intruders, it is almost impossible to survive.
But for an inland tribe like Kuafu, it is normal to make this decision. The earth is spherical, and it revolves around the sun. They know nothing about the geography of northwest China. They may know at most from the tribes near the Yellow Sea and Bohai Sea that the east is the sea and the sun rises from there. As for the west, the end is the Jade Valley, and the sun sets.