Three-days-before-and-after rule

The Three-days-before-and-after rule is a practical discipline for making change responsibly: examine the causes of a turning point, prepare people for action, and review what has been done. Its appearances connect careful timing not with hesitation for its own sake, but with the difficult work of restoring order and ensuring that reform has a sound beginning and a good end.

Formulation and Purpose

In the account of the condition represented by Kû, the rule accompanies a forecast of progress and success for anyone who deals properly with decay. The work may require crossing a great stream, an image of substantial effort; but effort alone is not enough. The text also requires weighing the events of the three days before the turning point and the measures to be taken in the three days after it. The instruction thus places diagnosis and response alongside decisive action.

The commentary explains why this scrutiny matters. Kû describes things going to ruin, as if through poison or venomous worms, and its auspice of progress depends on arresting that decay and restoring soundness and vigour. The crossing signifies the scale of the effort required, while the three-day inquiry directs attention both backward, to the events that produced the trouble, and forward, to the remedies needed to correct it. The rule makes restoration a considered undertaking rather than an impulsive attempt to repair what has failed.

Notice and Reconsideration

A second formulation makes the timing more explicit: with firm correctness, a person can act advantageously even when the beginning was not good, because a good end remains possible. Before making changes, notice is to be given three days in advance; three days afterward, the changes are to be reconsidered. Good fortune follows this sequence. Advance notice makes change an announced act rather than a surprise, and the later review tests the action after it has been undertaken.

The two intervals serve related but distinct purposes. The backward-looking inquiry in the Kû commentary studies the circumstances that brought on decay and the measures that may remedy it. The formulation about notice and reconsideration sets out a temporal procedure: prepare before acting, then look again after action. Together they link responsible change to causes, communication, and review, rather than treating good intentions or firmness alone as sufficient.

Relation to the Book's Structure

The rule appears in a text that the translator distinguishes from its later Appendixes. The central Text is attributed to King Wen and his son, the Duke of Zhou, while the Appendixes are treated as a later and historically distinct layer. The translator argues that blending the two can obscure the meaning of each, noting that editions had printed five Appendixes alongside the Text and that the resulting mixture confused readers. This distinction matters to the rule's interpretation: its practical instructions belong to a work whose received form and commentary history require attention to layers, sequence, and context.

The book's later transmission also illustrates how interpretation accumulated around such instructions. A catalogue prepared by Liu Xin near the beginning of the Common Era listed works on the Yî and its Appendixes from thirteen authors or schools, comprising 294 portions. The imperial Khang-hsî edition, first published in 1715, quoted 218 scholars, and its editors' discussions and decisions helped raise interpretation of the Yî toward a science. The translator also credits that edition as a major resource. This long history of commentary gives the rule a double significance: it prescribes careful review of change, and it has itself been read through successive acts of scholarly comparison and judgment.