Governance of the Kingdom from the Center are the only benefit is when the parents die, part of the Kingdom, also continues to be stable until a successor to the throne, the strong man.
The majority ruled from the center are two of the only good part is when a parent dies, the other realms, it continues to be steadily until his successor to the throne, another strength.
Rule of two big empire from the good effect is only when parents any part died, the Kingdom part still continue firmly to the throne again until he was strong.