As a divinatory line, nine at the third place of The Well reads within the hexagram's overall concern with a town may be changed while the fashion of its wells is never changed, the well neither decreasing nor increasing, and all who come and go draw from it and are benefited. The line occupies a place proper to its own nature in the classical doctrine that odd places favour a firm, yang line and even places favour a yielding, yin line. Its own text, that the well cleared out yet unused, occasion for grief, though the water might still be drawn if the king were only wise, is the particular fortune assigned to this one stage of the situation, not to the hexagram as a whole.
The third line corresponds by classical convention with the sixth line, and the two correspond here, since one line is yin and the other yang. Read together with the trigram it belongs to, Xun in the lower position of the figure, the line marks the hinge between the two trigrams, the last word the lower trigram gets before the upper trigram takes over, one stage in the six stage movement the hexagram traces from its first line to its last.
A change at this line, from yang to its opposite, is the mechanism the tradition uses to move from one hexagram to another. Flipping the third line of The Well turns Xun into Kan while the other trigram, Kan, stays as it is, which yields The Well's changing partner, The Abysmal (King Wen 29), the hexagram this line is recorded as transforming into.