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Drawing ensō is a disciplined-creative practice of Japanese ink painting, sumi-e. The tools and mechanics of drawing the ensō are the same as those used in traditional Japanese calligraphy: One uses an ink brush to apply ink to washi (a thin Japanese paper).
The circle may be open or closed. In the former case, the circle is incomplete, allowing for movement and development as well as the perfection of all things. Zen practitioners relate the idea to wabi-sabi, the beauty of imperfection. When the circle is closed, it represents perfection, akin to Plato's perfect form, the reason why the circle was used for centuries in the construction of cosmological models (see Ptolemy).
Usually, a person draws the ensō in one fluid, expressive stroke. When drawn according to the sōsho (cursive) style of Japanese calligraphy, the brushstroke is especially swift. Once the ensō is drawn, one does not change it. It evidences the character of its creator and the context of its creation in a brief, continuous period of time. Drawing ensō is a spiritual practice that one might perform as often as once per day.
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).
Use outside of Zen Buddhism
- Design Studio CREATE108 uses an Ensō in their logo, which also refers to the letter C of the word Create(108).
- The design of Apple Campus 2, Apple Inc.'s ring-shaped corporate headquarters, might also have been inspired by the ensō.
- AMD uses an ensō in the marketing of its Athlon & Ryzen processors with the Zen microarchitecture.
- Some editions of philosopher Joseph Campbell's book, The Hero with a Thousand Faces, bear this symbol on their cover representing creativity and uninhibited freedom of expression within art/literature.
- HSBC bank released a card named zero using as logo an ensō.
- Between 1995 and 2006, Lucent Technologies used a red ensō logo, designed by Landor Associates, meant to convey creativity and urgency.
- The book The Lean Startup uses an enso on the cover. One of the concepts in the approach includes a learning cycle 'Build - Measure - Learn".
- A mobile smartphone app for meditation is called Ensō. 
- Enso Gallery in Malibu, California features the zen-inspired enso paintings of local artist Tyler L. Barnett. 
- MINDBODY prominently features an ensō in its company logo.
- The Ensō bootloader vulnerability that allows the HENkaku exploit in PlayStation Vita consoles to run permanently uses an ensō as its logo.
- KOAN Sound uses an open ensō in their logo as the 'O' character.
- EnsoData, a company in Madison, WI, created an AI algorithm called EnsoSleep for use in sleep medicine 
- A generative crypto art project by artist-programmer Matto called "Ensō" uses a cryptocurrency transaction hash to mimic the painting of ensōs.
- Abstract expressionism, a 20th-century American art movement
- Buddhism in Japan
- Dhyāna in Buddhism, a meditation practice in which the observer detaches from several qualities of the mind
- Ink wash painting, an East Asian style of brush painting that uses black ink
- Ouroboros, an ancient symbol depicting a serpent or dragon eating its own tail
- Tanahashi, Kazuaki (2013). Treasury of the True Dharma Eye. Shambhala. p. 1115. ISBN 978-0-8348-2836-0.
圓相 [ensō], literally, circle form. Represents enlightenment. 團圝 [danran], literally, circle round. Represents intimacy.
- Seo, Audrey Yoshiko (2007). Ensō: Zen Circles of Enlightenment. Boston: Weatherhill. ISBN 9780834805750. OCLC 71329980.
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- Bowie, James (9 May 2006). "The Lucent Logo Legacy: Long Live the Big Red Donut". American Institute of Graphic Arts. Archived from the original on 11 October 2007. Retrieved 25 November 2013.
- McGowan, John (17 March 1997). "Elucidating Lucent's "Million-dollar Coffee Stain"". CNNMoney.com. Time Warner. Archived from the original on 3 December 2013. Retrieved 27 November 2013.
- "The 12 Best Meditation Apps For 2020". Retrieved 31 July 2020.
- "Imperfectly Perfecty". Retrieved 31 July 2020.
- "EnsoData". Retrieved 23 June 2021.
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