Withdrawal rather than struggle is what this line makes available, and its structure is why: a yin stroke stands in an even position, correctly placed by the standard rule, and a yielding line in a yielding place can give ground without loss where a firmer line might feel bound to hold it. It occupies the lowest position of the upper trigram Kan, the point at which the hexagram's danger is first fully entered, and its counsel to retreat rather than persist marks a genuine turn in the hexagram's logic, from patience exercised at a distance to patience that includes knowing when to step back.
When this line changes, Kan's bottom stroke becomes firm, turning the upper trigram into Dui, the joyous lake, while Qian remains fixed below. The resulting hexagram is Number 43, Breakthrough, lake over heaven, the image of an accumulation of yang strength about to overtop a single remaining yin line at the very top, and a Judgment that calls for the matter to be announced openly rather than met with force. That a line counseling quiet withdrawal from a dangerous position transforms into the hexagram of open, resolute breakthrough is one of the more striking pairings in this set of six, retreat from one kind of difficulty setting up the conditions for a later, decisive advance against another.