Inseparable as Form and Shadow

形影一如 (keiei ichinyo): form and shadow as one; two who are never apart. 形影 is the body and its shadow, the pair that never parts, an image the Chinese poets used of an exile whose soul went home while her form and shadow stayed on the barbarian plain; 一如 is the Buddhist not-two, one thing under two appearances. The four together are a rare phrase. One dictionary lists them, with two senses, that what is in the heart shows in what a person does, and that husband and wife are close; the great national dictionary has no entry, and the National Diet Library's index finds the phrase in four books in a century. Its oldest real use is a Zen one: a book telling how the Tang master Dongshan, crossing a river, saw his reflection in the water and was awakened, form and shadow as one, and made the verse that begins do not seek from another, or you will be far from yourself. The other use is of two men who worked side by side for twenty years. So the phrase is a Zen image that a dictionary offers to a devoted couple: beautiful, uncommon, and no one's proverb. The Chinese phrase for two people who are never apart is 形影相随, form and shadow following each other, and the old Japanese word for a couple is 異体同心, bodies apart and one heart; this one says that two people are as close as a body and its shadow, which is the closest thing there is. 形影一如 is composed of the word 形影 (read keiei) with the characters meaning "form and shadow" and the word meaning "inseparable" and 一如 (read ichinyo) meaning "oneness".

形影一如 is given as an anniversary or wedding gift for a couple who are never apart.