Learning from history, we can see the way of the rise and fall of empires: Liu Bang and Zhu Yuanzhang both cleaned up their entrepreneurial officials after ascending to the throne, and the emperor of the cloth, in particular, needed to be cold and ruthless in order to achieve great things. Not out of selfishness, but the power to force, strong emperor in the world can still suppress everything, once the old and weak, his successor will face the manipulation of meritorious group, hostage, and even subvert its "original intention". Therefore, the person who is generous and lenient, it is often difficult to long-lasting peace and security. Like the sky, changed color.