Below is an excerpt from an interview with aikido shihan Endo Seishiro, where he explains the "Tao" in martial arts. The full article may be read here.
We previously inquired about sensei's aikidô training about ten years ago (issue 106). This time we would like to ask about sensei's changes in his thoughts about aikidô since then, from the viewpoint of "dô" or Tao.
Japanese people have a tendency to attach "-dô" to everything. This can be seen not only with budô but also with sadô (or chadô, the art of tea ceremony) and kadô (the art of flower arrangement), for instance. We even hear of sumô-dô, salaryman-dô, keiei-dô (the way of business). People attach "-dô" to various aspects and activities of our lives in order to give them special meaning or to distinguish them as areas of mastery. Yet, I don’t think many people, including myself, really know what "dô" is. At some point I began to wonder why there were to ways to say one thing e.g. budô/bujutsu, kendô/kenjutsu, jûdô/jûjutsu, aikidô/aikijutsu, and thus started to explore the difference in meaning.
I feel I more or less have a grasp of the meaning of "jutsu," but when it comes to "dô," I feel it means something immense, deep, wide, and unclear. In my desire to somehow make it clearer, I sought books relating to Taoism, Lao-tzu (Lao-zi) and Chuang-tzu (Zhuang-zi). Tao can also be found in Confucianism and its virtues: Jin (仁, humanity), Gi (義, righteousness), Rei (礼, propriety), Chi (智, wisdom), Shin (信, faithfulness). It is said that Tao is to seek and realize, and thereby equip the self with, these virtues. We might say that this is "Tao for the people."
According to Taoism these virtues comprise a Tao as conceived by humans, and true Tao is that which has existed before this artificial Tao ever came into being. Lao-tzu expressed as follows: "The path that can be regarded as The Path is not the great eternal Path. The name that can be named is not the enduring and unchanging name1." This means that Tao is a fundamental, universal principle that has always existed before any artificial Tao came into being.
In Chuang-tzu's book of "Chi-hoku-yû" (荘子 知北遊篇)2, it is written, "There is nowhere that Tao is not. It is everywhere." The entire universe is Tao, and it is ki that gives birth and life to all the phenomena in the universe. It is also said that in order to know that ki and the flow of ki, one must know Tao. It appears that this is the origin of the words, "Seeking Tao," and "Mastering Tao." Lao-tzu referred to one who has mastered Tao as "mu-i-shi-zen" (無為自然, natural and unaffected). Chuang-tzu interpreted this as "emptiness unlimited" or "absolute nothingness3." When one grasps and masters the flow of ki of all the phenomena in the universe as it is, one is in the state of "mu-i-shi-zen" and "absolute nothingness." To strive to attain such a state is a true way of life for humans. This is what Taoism teaches.