The first line of Dispersion (King Wen 59) is drawn as yin, the numeral six in the old divination manuals. James Legge's translation renders the line as using a strong horse to rescue from impending trouble, good fortune. The image sits inside a hexagram whose judgment as a whole concerns progress and success, the king approaching his temple, advantage in crossing the great stream, advantage in being firm and correct, 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 Xun, wind in the same traditional set of images. The Great Symbolism of the hexagram reads wind moving above water; the ancient kings presented offerings to God and established the ancestral temple, and the first line takes its place inside that combined picture of Kan below and Xun 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, Using a Strong Horse to Rescue, as the concrete case through which the hexagram's abstract judgment becomes visible in a single situation rather than a general principle.