Form is emptiness: everything that has a form has no fixed nature of its own, and, in the half of the line the scroll leaves unsaid, emptiness is nowhere but in form. The four characters are the first half of a pair from the Heart Sutra, the line chanted in every Japanese school, and the pair is a statement about how the world exists, not a verdict on it; a Noh play turns it into an affirmation, because form is emptiness just as it is, the willow is green. 色 is form, matter, not color; 空 is emptiness, not nothingness. All is vanity, a dictionary's third gloss for the line, is the Preacher's verdict that everything is fleeting, and the two lines share only a character, and only in Japanese. The scroll carries the first half alone, as the tradition writes it; the second half is yours to know.
We want you to be as happy with the meaning as you are with Master Takase's art. To learn more, visit Philology of 色即是空.