As a divinatory line, nine at the fourth place of Revolution reads within the hexagram's overall concern with believed in only once it is accomplished, great progress and success, advantage in being firm and correct, so that any occasion for repentance disappears. 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 occasion for repentance disappearing, if he is believed in even while changing existing ordinances, there will be good fortune, is the particular fortune assigned to this one stage of the situation, not to the hexagram as a whole.
The fourth line corresponds by classical convention with the first line, and the two do not correspond here, since both lines share the same character. Read together with the trigram it belongs to, Dui in the upper position of the figure, the line marks the first word of the upper trigram, close enough to the ruling fifth line to be shaped by it, 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 fourth line of Revolution turns Dui into Kan while the other trigram, Li, stays as it is, which yields Revolution's changing partner, After Completion (King Wen 63), the hexagram this line is recorded as transforming into.