The fourth line of Breakthrough (King Wen 43) is drawn as yang, the numeral nine in the old divination manuals. James Legge's translation renders the line as buttocks stripped of skin, walking slowly and with difficulty, one who will not listen though the words are plain. The image sits inside a hexagram whose judgment as a whole concerns the culprit's guilt exhibited at the royal court, with sincere and earnest appeal, and a consciousness of the peril in cutting the criminal off, 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 upper trigram Dui, lake in Legge's readings of the eight trigrams, while the lower trigram of the hexagram is Qian, heaven in the same traditional set of images. The Great Symbolism of the hexagram reads the waters of a marsh mounted above heaven; the superior man bestows his gifts on those below rather than letting them accumulate unused, and the fourth line takes its place inside that combined picture of Qian below and Dui above.
Read on its own the line neither opens nor closes the hexagram's argument. It marks the point where Dui is either forming (in the lower trigram) or completing itself (in the upper), and later interpreters treat its image, The Buttocks Stripped of Skin, as the concrete case through which the hexagram's abstract judgment becomes visible in a single situation rather than a general principle.