The first line of Youthful Folly opens the hexagram with correction rather than encouragement. Legge's translation gives the line as the dispelling of ignorance, adding that it will be advantageous to use punishment for that purpose. The word rendered punishment in this context points to the traditional practice of applying clear, even severe, boundaries at the very outset of instruction, not cruelty for its own sake but the firm shape that untaught impulse needs before it can be guided any more gently.
This is the lowest place of the lower trigram Kan, water, the trigram Chinese tradition associates with danger and with the middle son, here doubled beneath the upper trigram Gen, mountain, associated with stillness and the youngest son. A dangerous spring welling up at the foot of a mountain, not yet knowing its own course, gives the hexagram its central image, and the first line shows that untaught water at its rawest: real potential, entirely undirected, in need of a firm bank before it becomes a channel.
Chinese commentary tradition reads this line as counsel for the earliest stage of teaching any pupil, tempering firmness with a caution of its own: correction applied too harshly, or for its own sake rather than the pupil's benefit, becomes as much a fault as ignorance left uncorrected. The line's placement at the very base of the hexagram marks it as foundational, the setting of a pattern that later lines, forbearance, warning, isolation, openness, will each answer according to how well this first correction was made.