As a divinatory line, nine at the fourth place of Oppression reads within the hexagram's overall concern with one in straits may yet find progress and success; for the firm and correct, the truly great man, there is good fortune and no error, though his words will not be believed. 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 proceeding very slowly, straitened by a carriage adorned with metal in front, occasion for regret but the end will be good, 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 correspond here, since one line is yin and the other yang. 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 Oppression turns Dui into Kan while the other trigram, Kan, stays as it is, which yields Oppression's changing partner, The Abysmal (King Wen 29), the hexagram this line is recorded as transforming into.