The ensō symbolizes absolute enlightenment, strength, elegance, the universe (Dharmadhatu), and mu (emptiness).
An empty circle also appears in the ten oxherding pictures which is a set of illustrations that depict Zen training.
The space inside the circle may represent the state of the realization of emptiness (shunyata) or no-mind.
[2] This spiritual practice of drawing ensō or writing Japanese calligraphy for self-realization is called hitsuzendō.
Ensō exemplifies the various dimensions of the Japanese wabi-sabi perspective and aesthetic: fukinsei (asymmetry, irregularity), kanso (simplicity), koko (basic; weathered), shizen (without pretense; natural), yugen (subtly profound grace), datsuzoku (freedom), and seijaku (tranquility).