This term means two types of imperial decrees in ancient times. Xi (檄) was an official condemnation of the enemy and an official rallying call to fight, whereas yi (移) was an admonition released to the public to advise people against improper speech and behavior. As Liu Xie (465?-520) remarked in his literary critique The Literary Mind and the Carving of Dragons, an imperial decree of condemnation was written to list atrocities committed by the enemy, boost soldiers' morale, win popular support and demoralize enemy troops. Therefore, it was compelling and forceful, and well-articulated, supported by ample reasoning and proofs. Where necessary, overstatement, exaggeration or even deceitful wording can be employed in such a decree. An admonition, on the other hand, was written to expose problems or vices inside the empire, alert the public to their harmful effects and demand their timely rectification. Because an admonition was issued to one's own subjects, it should be more compassionate and lenient in tone. An admonition should be factual, without pomposity or fanfare. It should get right to the heart of a problem rather than beating about the bush or even concealing the truth. A condemnation and an admonition share one thing in common: they were stern in denouncing evildoing and malpractices.

The character xi means bright and clear, as in "clear as daylight." It is meant to clarify issues to the public. (Liu Xie: The Literary Mind and the Carving of Dragons)

A decree of condemnation is written to declare that justice is on our side and to expose the brutal nature of the enemy. It should spell out the strategic environment, compare our strengths and weaknesses with those of the enemy, and warn the enemy about its doom by citing past examples. (Liu Xie: The Literary Mind and the Carving of Dragons)

Yi (移) and yi (易) are two Chinese characters with almost the same sound interchangeable in this context,both meaning change. A decree of admonition aims to change improper customs and practices. Wherever such a decree reaches, people will obey it and change their customs. (Liu Xie: The Literary Mind and the Carving of Dragons)