As a divinatory line, six at the first place of Obstruction reads within the hexagram's overall concern with advantage found in the southwest, and the contrary in the northeast, advantage in seeing the great man, and in being firm and correct. 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 going forward leads to difficulty, remaining still brings ground for praise, 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, Gen 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 yin to its opposite, is the mechanism the tradition uses to move from one hexagram to another. Flipping the first line of Obstruction turns Gen into Li while the other trigram, Kan, stays as it is, which yields Obstruction's changing partner, After Completion (King Wen 63), the hexagram this line is recorded as transforming into.