As a divinatory line, nine at the first place of The Marrying Maiden reads within the hexagram's overall concern with action taken now will be evil, in no way advantageous. 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 the younger sister married off in a secondary position, lame on one leg yet still able to walk, good fortune in going forward, 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 do not correspond here, since both lines share the same character. 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 The Marrying Maiden turns Dui into Kan while the other trigram, Zhen, stays as it is, which yields The Marrying Maiden's changing partner, Deliverance (King Wen 40), the hexagram this line is recorded as transforming into.