The first line of Oppression (King Wen 47) is drawn as yin, the numeral six in the old divination manuals. James Legge's translation renders the line as bare buttocks straitened under the stump of a tree, entering a dark valley and for three years having no prospect of deliverance. The image sits inside a hexagram whose judgment as a whole concerns 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, and this line supplies one stage of that larger reading rather than a complete statement on its own.
Structurally the line stands at the lowest place of the lower trigram Kan, water in Legge's readings of the eight trigrams, while the upper trigram of the hexagram is Dui, lake in the same traditional set of images. The Great Symbolism of the hexagram reads a marsh with no water in it, drained dry by the pit beneath; the superior man will sacrifice his life to carry out his purpose, and the first line takes its place inside that combined picture of Kan below and Dui above.
Read on its own the line neither opens nor closes the hexagram's argument. It marks the point where Kan is either forming (in the lower trigram) or completing itself (in the upper), and later interpreters treat its image, The Bare Buttocks Straitened Under the Stump, as the concrete case through which the hexagram's abstract judgment becomes visible in a single situation rather than a general principle.