As a divinatory line, nine at the first place of Inner Truth reads within the hexagram's overall concern with reaching even pigs and fish, good fortune, advantage in crossing the great stream, advantage in being firm and correct. 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 resting in himself, good fortune, since if he sought elsewhere he would find no rest, is the particular fortune assigned to this one stage of the situation, not to the hexagram as a whole.
The first line corresponds by classical convention with the fourth line, and the two correspond here, since one line is yin and the other yang. Read together with the trigram it belongs to, Dui in the lower position of the figure, the line marks the opening of the situation, before the trigram above it has any part in the reading, 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 first line of Inner Truth turns Dui into Kan while the other trigram, Xun, stays as it is, which yields Inner Truth's changing partner, Dispersion (King Wen 59), the hexagram this line is recorded as transforming into.