If Gòu has appeared in your reading, the book is naming the inverse moment of Fù (Return). Where Fù is the first yang line returning at the bottom — the seed of light in the heart of winter — Gòu is the first yin line entering at the bottom of a strongly yang hexagram. A small element has appeared in a field that did not have it before. It looks minor. The book is warning that minor is not the same as inconsequential.

Classical commentary reads this hexagram as the test of early recognition. The yin line at the bottom seems trivial against the five yang lines above; left alone, it will grow. The hexagram appears when something has entered the reader's situation — a person, an offer, a small commitment, a habit — that the reader is tempted to dismiss as too small to attend to. The book is recommending the opposite.

What the book counsels is the clarity of early naming. 施命誥四方 — proclaim the order, announce it to the four quarters. Set the principles publicly while the new element is still small enough to be addressed by the principles. The cost of doing this is minor; the cost of not doing it, the book suggests, can become major. The vigilance is preventive, not reactive.

Gòu's failure mode is the polite minimisation of the new element. The book is alert to it. The hexagram appears when the reader has noticed something but is choosing not to act on it because acting feels disproportionate. The book is reframing the proportion. The element is small now. The window in which it can be addressed cheaply is also now, and not later.