The imperial court is a big country with subordinate counties. When the county has a certain area, there will be more (in ancient times, there was a "state", eldest brother A inherited the largest territory of the country, and other sons could only inherit a small territory. When the eldest son of elder A inherited most of A's fiefs, other sons of elder A got a small part of A's territory. ), the smaller their actual strength and ability, the smaller their ability to fight against the central country.

On the other hand, there may be interests involved among small counties and countries, and they cannot unite as one, which is more conducive to the unified jurisdiction of the central court.

Internal harmony is also a good opportunity to clear the surrounding threats.