The Japanese Calligraphy Brush Stroke of a circle or Ensō (円相) signifies No Beginning, No End. It symbolizes many things or aspects, such as the Universe, enlightenment, vigor, simplicity, gracefulness, and also emptiness.
The stroke itself is known as Hitsuzendo (筆禅道), which means the “Art of the Brush.” And some Buddhists believe it to be a method of achieving Samādhi, which means a unification of individual with the highest reality or an awakening or enlightenment (Kenshō 見性). This is also consider another form of meditation. e.g., there is sitting (坐禅 Zazen), walking, chanting (念仏 Nembutsu), and Japanese Calligraphy.
The logo/embelm also demonstrates veneration for Shākyamuni Buddha, who was the first enlightened/awakened being, also known as Siddhārtha Gautama and Śākyamuni (Sanskrit: सिद्धार्थ गौतम), as well as all of his proceeding disciples in later generations/transmissions, such as Eihei Dōgen Zenji of the Sōtō Zen Buddhism, which Mahāyāna (sanskrit महायान) Buddhism derives from.
It is also a symbolic reminder of one’s dedication to one's oractice of Buddhism, which includes one’s Vows as a Buddhist/practitioner, and one’s Zazen or Shikantaza (“just sitting” ~ Dōgen Zenji). Moreover, it illumines that one needs to be balanced and thus, display the Middle Way (also coined by the aforesaid Zen Master).
Furthermore, the Katakana Kanji (カタカナ) is three characters that represent Karatedo (空手道) or the Empty-Handed Way. The Way or Do ("doh") means a philosophy or concepts that one dedicates oneself to wholeheartedly. Uchideshis (内弟子) or live-in disciples of a master demonstrate this Karatedo, and thus, are Karatekas (空手家), which is one that practices karate.
Juxtaposed, it reflects one’s commitment to Genjōkōan Karate, which has its roots from Okinawa, Japan, and includes the perceptions, influences, tenets, and philosophies of China and India as well.
Moreover, akin to Shākyamuni’s statue placed on Buddhist's altars, the Karatedo kanji serves its purpose as a reminder of one’s discipline, veneration, and commitment to Mahāyāna (Great Vehicle) Buddhism originating in India, then to China, and finally Japan, and to the Genjōkōan Karate Organization.
The silver-colored kanji represents the chemical attributes of this property or element; e.g., it possesses the highest electrical conductivity of ANY element on the Periodic Table, as well as the highest thermal conductivity (the property of it reflecting an ability to conduct heat itself) of ANY metal.
So, possessing electrical and thermal conductivity is conducive, because chanting, sitting, sweating, and finding the Middle Way also known as the Two Truths depends on finding harmony within the planet, the universe, and of course, oneself.
Therefore, sounds, vibrations, electromagnetic currents, etc., assists
in one reaching an enlightened state of mind or true reality, which can
be referred to as Samādhi समाधि
, Nirvana 涅槃, Kenshō見性, or becoming a Bodhisattva 菩薩, which is an enlightened/awakened being (a Buddhist) who vows to help all sentient beings.
The outer silver circle that encompasses the kanji and Ensō represents the unity of all sentient beings; i.e., it symbolizes the lack of subject/object perspective and therefore, one’s ego or “I” viewpoint for true actualization of reality or an embracing one, such as “you are me and I am you”; i.e., an interdependence between all sentient beings as opposed to a separation, which is the delusional mind, which is based on abstract reality or not True Reality, which is reached via one's Zazen (mediation: Shikantaza 只管打坐 ).
The white background represents attributes of reflection: "What is this world like? As a waterfowl shakes its bill. On each drop of water, the Moon is reflected" (140). ~ Waka Poem by Dōgen Zenji from Realizing Genjōkōan; i.e., a drop of water, like the color white, can reflect anything in its entirety; it envelops and reflects at the same time, thus, it is non dual (two separate/discriminate things happening simultaneously), but rather a oneness (indiscriminate), which reinforces an interdependence (Universality) or cosmic connection to another thing or sentient being (s) known as Interconnectedness.
So, as Zazen 坐禅 teaches one to sit quietly and let thoughts or secretions in/of the brain flow unobstructed. i.e., freely without clinging to them or ruminating on them, one can thus, see/reflect and therefore, awaken to one’s True Reality and not be stagnant in the intellectually abstract one (so-called reality) that most reside/dwell in.
Below are three eloquent adages or opines of/from Zen Masters/Bodhisattvas/Monks that demonstrate the aforesaid points.
“The perfect circle of the mind-moon is alone; its light swallows ten-thousand things. The light does not illuminate objects; neither do objects exist. The light and objects both cease to exist; what is this?” (136) ~ Panshan Baoji/Banzan Hoshaku from Realizing Genjōkōan.
“The truth of the Middle refers to seeing the reality of each and every being from both the side of emptiness ('there is not') and from the side of temporal being ('there is')” (133). ~ Shohaku Okumura from Realizing Genjōkōan.
"To study the Way is to study the self. To study the self is to forget the self. To forget the self is to be enlightened by all things. To be enlightened by all things is to remove the barriers between one's self and others." ~ Eihei Dōgen Zenji from Shōbōgenzō Zuimonki.