Why do monochromatic feathers face themselves in archery?

The monochromatic feather is called the main feather, and the main feather should be outward when releasing the arrow, so that this horizontal feather will not squeeze the bow handle (or the arrow seat on the bow handle) and affect the precision after deployment.

Because Mediterranean archery is on the left, the main feather is aimed at itself. If the traditional bow is shot by Mongolia and the arrow is on the right, then the main feather is in the opposite direction to the person.

In addition, in ancient China, the main feather was upward, but now it is outward, influenced by the West.