Qin relied on allies bearing the same surname to establish its ascendency.
Eric Henry
In its days of decline, it did not change its reliance on same-surname allies, but the ruler lost his life and the state was destroyed.
故王者之治天下，在於行法，不在於信同姓。
Eric Henry
Thus, we can see that the ability of a ruler to establish sway over the realm lies in promoting rule by law, not in placing trust in those of the same surname.