As a divinatory line, nine at the sixth place of Increase reads within the hexagram's overall concern with advantage in every movement undertaken, even advantage in crossing the great stream. 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 none add to his increase, and some will even assail him, since he sets up no rule to keep his mind constant, evil, 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 correspond here, since one line is yin and the other yang. 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 Increase turns Xun into Kan while the other trigram, Zhen, stays as it is, which yields Increase's changing partner, Difficulty at the Beginning (King Wen 3), the hexagram this line is recorded as transforming into.