Cheth is written as a fully closed shape, its left leg unbroken from roof to base, which sets it apart in Jewish scribal practice from its near-twin Heh, discussed elsewhere in this atlas, whose otherwise identical outline leaves a small deliberate gap in the same corner. A widely repeated homiletic teaching, common in popular and Chassidic writing on the Hebrew letters, draws directly on that contrast together with a pun on the letter's name: the Hebrew word for sin or transgression, cheit, begins with Cheth, and the letter's total enclosure is read as a figure for the way wrongdoing can seem to seal a person in without an exit, while Heh's open gap next door represents the path of repentance always left available. A sofer copying Cheth must take particular care that the closure is genuine and unbroken, since a gap that creeps in by accident risks turning the letter into a Heh and invalidating the word, the reverse of the more famous confusion between Dalet and Resh discussed elsewhere in this atlas.
Cheth is one of the Sefer Yetzirah's twelve simple letters, a classification covered separately from this scribal history, and its name, meaning a fence or enclosure, already carries the same idea of total closure that the Heh-Cheth homily draws on, an unusual case where a letter's literal Semitic meaning and its later homiletic reading point in exactly the same direction.