As a divinatory line, six at the fourth place of Keeping Still reads within the hexagram's overall concern with resting like the back, so one loses all consciousness of self, walking in one's own courtyard and not seeing the persons in it, no error. 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 keeping the trunk of the body still, no error, 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, Gen 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 yin to its opposite, is the mechanism the tradition uses to move from one hexagram to another. Flipping the fourth line of Keeping Still turns Gen into Li while the other trigram, Gen, stays as it is, which yields Keeping Still's changing partner, The Wanderer (King Wen 56), the hexagram this line is recorded as transforming into.