The withdrawal this line describes is measured and unforced, and its placement suits it exactly. A yin stroke stands in an even position, correctly placed by the standard rule, fit for a considered retreat rather than for any forced advance it is not equipped to sustain. Positioned at the foundation of the upper trigram Kun, the point where the army first rejoins the larger body it belongs to, its retreat is a return rather than a defeat. When this line changes, the bottom stroke of Kun becomes firm, turning the upper trigram into Zhen, thunder and sudden movement, while the lower trigram Kan remains fixed below.
The resulting hexagram is Number 40, Deliverance, thunder over water, an image of tension finally released, the relief that follows a difficulty successfully passed rather than one still being endured. That a sensible tactical withdrawal, rather than being read as a setback, should transform into the hexagram of deliverance confirms the line's own framing: stepping back from an unfavorable position at the right moment is not merely blameless, it is precisely what allows the pressure of the campaign to ease rather than accumulate into a harder trial later. Commentary on Deliverance elsewhere in the tradition treats it as following naturally from difficulty correctly handled rather than from difficulty avoided altogether, which fits this line's own careful, undramatic retreat.