As a divinatory line, nine at the sixth place of Development reads within the hexagram's overall concern with the marriage of a young lady, and the good fortune attending it, advantage in being firm and correct. The line occupies a place that does not match 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 geese gradually advancing to the heights above the ordinary flight path, their feathers fit to be used as ornaments, good fortune, is the particular fortune assigned to this one stage of the situation, not to the hexagram as a whole.
The sixth line corresponds by classical convention with the third 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 upper position of the figure, the line marks the far edge of the hexagram, past the point the ruling fifth line governs, 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 sixth line of Development turns Xun into Kan while the other trigram, Gen, stays as it is, which yields Development's changing partner, Obstruction (King Wen 39), the hexagram this line is recorded as transforming into.