If Sòng has appeared in your reading, the book is naming a structural friction — not a personal failing on either side, but a configuration in which two genuine forces have been set against each other. The trigrams say it cleanly: heaven moves up, water moves down, and there is no posture in which they meet.
Classical commentary reads this hexagram as the moment after Xū, the long waiting. When the wait is over and the question of allocation arises — who gets the rain, who gets the river crossing — conflict is the natural next form. The book is not condemning the disagreement. It is examining what to do inside it.
What the book counsels is wariness in the middle and disengagement at the end. 中吉, 終凶 — the middle can be auspicious, the end is grim. Do not chase the fight all the way down. Seeing the great person — appealing to a third party with standing — is favoured; crossing the great river, committing to large undertakings while the conflict still runs, is not. This is a hexagram about strategic restraint, not capitulation.
Sòng's danger is the appetite for being right. The book treats this appetite as expensive. Even a fight you would win consumes what you need for the next thing. The wise move is usually to take the partial settlement, withdraw with the structure intact, and let the next season find a different ground.