If Dà Chù has appeared in your reading, the book is naming the configuration of significant power that has been gathered and is being held in disciplined reserve. Heaven below, Mountain above: the most active trigram contained within the most stable. The energy is there. It is not yet spent.

Classical commentary reads this hexagram as the discipline of accumulation. The reader has been preparing — through study, through practice, through the patient banking of skill and resource — and the gathered capacity is now substantial. The hexagram appears when the question is what the gathering is for, and how it is to be used.

What the book counsels is service at the public table. 不家食 — do not eat at home. The accumulated strength is not for private nourishment; it is for the larger work. The clearance 利涉大川 — fitting to cross the great river — is the book's confirmation that the reserve is genuinely sufficient for a serious undertaking. Major moves are favoured, on the condition that they are undertaken in the open.

Dà Chù's failure mode is the hoarding of the reserve. The hexagram is uneasy with private accumulation that never reaches deployment. The image of heaven held inside the mountain assumes that the heaven is still moving inside the form — not crystallised into something inert. The accumulation is the prelude. The hexagram is asking what the prelude is for.