emptiness is form; form is emptiness
A core Mahayana Buddhist concept from the Heart Sutra, paired with 色即是空. It teaches that emptiness (空) does not negate form (色) but is identical with it; the material world is an expression of emptiness.
See also: 色即是空
「空即是色」は般若心経の有名な一節です。
"Emptiness is form" is a famous passage from the Heart Sutra.
The idea that form is emptiness and emptiness is form expresses the essence of things.