Said of a tremendous force that cannot be resisted.
CAO Cao of the state of Wei in the north was the most powerful of the Three Kingdoms. He once threatened Sun Quan of the state of Wu, demanding that Sun Quan deliver his son to him as a "hostage". Zhou Yu, the chief general of Sun Quan, advised Sun not to yield to his threat. He said to Sun Quan, "We have a fine army, sufficient food, abundant produce and a convenient transport system. The minds of our people are at rest. As long as we can make full use of these conditions and work hard for the prosperity of the country, we shall certainly become unrivalled anywhere. Why let Cao Cao act as the head while you serve as his tail?"
History of the Three Kingdoms