As a divinatory line, nine at the third place of The Cauldron reads within the hexagram's overall concern with great progress and success. 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 caldron's ears altered so its progress is stopped, the rich fat within left uneaten, but a fall of rain brings the occasion for regret to a good end, 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 do not correspond here, since both lines share the same character. 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 Cauldron turns Xun into Kan while the other trigram, Li, stays as it is, which yields The Cauldron's changing partner, Before Completion (King Wen 64), the hexagram this line is recorded as transforming into.