The Japanese have six words referring to the intensity of training in any activity: keiko, renshu, shunren, tanren, kufu, and shugyo. The first four can be translated respectively as: practice, training, discipline, and forging. There are no adequate English words for the last two. Shugyō is the deepest spiritual training possible. In shugyō training there are two paths that may be followed, the first being the way of training the mind (kokoro) and the second of training the body( katachi) . Refining the self in shugyō is like forging a sword from raw iron ore. Fire, water, and iron are folded upon each other by the pounding of the hammer over and over again to create the cutting edge. One should keep in mind the principles of Shu, Ha, Ri, and be tenacious in the mastering of the fundamentals (kihon), so that the mind, the body and the weapon become one. If one delves into the kanji that make up the character, one finds Shu, which can be understood as practice or to engage in study; and Gyō, that can be understood as a juncture or crossroads. Hence, it is to persevere when one has reached a point where one has a choice to quit or proceed on the Way . Shugyō is the method of polishing the mind and body of a person through a means of rigorous training . If one engages in their training as such, the practitioner has the opportunity to refine not only their physical ability but the mental strength and stability in order to deal with the complications of life.
The dojo is not a place that one retreats to in order to hide or escape from the difficulties of life , instead it is the place that one meets their true inner selves and thus aims to improve ones character and learn how to cope with real life. If a man is to know himself, he must be tested; no one finds out what he can do except by trying . This is the heart of Shugyō, an austere training where the limits of physical endurance and performance are surpassed, where only the strength of character and the will of the spirit fuels one forward. Trying and being tested is the proof of good men . Without Shugyō, all realizations are passing highs. The natural form of the body will not be developed, nor will the structures of mind emerge from the Unconscious; and a person will regress to egotistical patterns under pressure. If a person trains to attain enlightenment as an end, frustration and despair is inevitable for the Way is endless. But if you accept life as shugyō, see through both good and bad fortune as the effects of karma, and continually refine breath, posture, and awareness, then one day you will clearly realize the truth of the words of Master Dōgen, Training is enlightenment, and enlightenment is training. At the heart of this is to discover the truth for oneself.
Therefore, it is of the utmost importance to keep in mind that one should never give up or quit. As one progresses in practice there will most assuredly come a time when the budōka questions his progress, or the reason for continuing in an art or way that is not popular and at times obscure. There may be times that he will be forced to confront the urge to quit as the demands of work, a spouse, or the aches of age become stronger. These doubts are not ones that will enter into the thoughts of an eager beginner as everything is quite exciting. But for the practitioner that has performed thousands of cuts in the refinement of his technique, this is a deep and important question. As now he has come to understand that the path of budō is an extremely difficult one; it is path that does not hold the rewards of fame and fortune. He may want to quit but he cannot, it is part of his life and he presses on in the spirit of shugyō.
The purpose of the practice of Budō is not for the sake of physical technique or strength. We continue in our practice through the adversities of life, the bone chilly winters, the blistering summers, and the humbling injuries, because we have come to acknowledge and learn about our true selves. A sincere involvement in the practice of Budō provides us with the rare chance to face ourselves. From these encounters when the ego is stripped away, we come to realize the essence of Budō( 武道), the way. We practice for the refinement and polishing of our character and spirit. It should then be understood with advancement, what is meant by the saying, if the heart is not true and correct, the sword will not be true and correct . There indeed should be an ascension in the character, maturity, and development with the advancement in rank and age. This development should be as a person, a being of the universe. Our continued practice in these obscure ways, serves as a way to preserve a significant cultural jewel, to develop ourselves, and to strive towards realizing our potential. Thus, a Budōka becomes more potent in spirit even though the vigor of youth gracefully falls away as cherry blossoms at the end of spring.
 N. Hisashi, The kendo reader (1939).
 D. Lowry, The Sword and thew Brush; Shambala Publications (1995).
 Japanese-English Dictionary of Kendo; All Japan Kendo Federation (2000).
 L. A. Seneca, Dialogues and Essays; Oxford University Press (2009).
 M. Miyazako, Kendo is my philosophy; Taiiku & Sports Publishing Co.Ltd (2010).
 T. Shimada, Path of the Sword.