Ensō

nihongo|Ensō|円相 is a Japanese word meaning "circle" and a concept strongly associated with Zen. "Ensō" is perhaps the most common subject of Japanese calligraphy, symbolizing enlightenment, strength, elegance, the universe, and the void; it is also an "expression of the moment" and thus is often considered a form of expressionist art.

Zen Buddhists believe that the character of the artist is fully exposed in how he paints "ensō", and that only one who is mentally and spiritually whole can paint a true "ensō". Some artists will paint "ensō" daily, as a kind of spiritual diary.

Some artists paint "ensō" with an opening in the circle, while others complete the circle. For the former, the opening may symbolize various ideas, for example that the "ensō" is not separate, but is part of something greater, or that imperfection is an essential and inherent aspect of existence (see also the idea of Broken symmetry).

The "ensō" is also a sacred symbol in the Zen school of Buddhism, and is often used by Zen masters as a form of signature in their religious artwork. See also "Hitsuzendo" for information about the Way of the Brush.

The "ensō" has also been co-opted as an advertising symbol by various companies, notably, Lucent. No longer used since the Alcatel merger, the logo was often jokingly referred to as the "coffee cup ring." The company Humanized uses "Ensō" as the name of a series of software products based on the work of Jef Raskin meant to simplify common computing tasks.

For a similar concept in Greek philosophy, see Monad.